We look at all Thursday's matches
Stuart Hogg's second-half score dished out a Boxing Day sucker punch to Edinburgh in their Pro12 encounter with Glasgow Warriors.
The Warriors took away the spoils with 20-16 win at Murrayfield on Thursday, which saw them move into the top three on the standings.
With Leinster and Ulster meeting in their Round 11 encounter on Saturday, Glasgow could finish the weekend with a top-four spot.
* In other action on Thursday Ospreys produced a determined defensive display to grind out a deserved 10-6 derby win at Parc y Scarlets on Boxing Day.
The result allowed the Welsh outfit to cement their place in the top four, moving up to second spot.
* There was no Christmas hangover at Rodney Parade as Jason Tovey led Newport Gwent Dragons to a 22-16 victory over Cardiff Blues in a breathless Boxing Day derby.
We look at all Thursday's matches!
Scarlets 6-10 Ospreys
Ospreys produced a determined defensive display to grind out a deserved 10-6 derby win at Parc y Scarlets on Boxing Day.
Rhys Priestland kicked a penalty in each half for the hosts and Dan Biggar notched one of his own, in an uncharacteristically wayward kicking display.
Hanno Dirksen had been denied a second-half try by the TMO but replacement Ian Evans did get the decisive score to win it for Ospreys late on.
Ospreys ventured into opposition territory early on but after kicking his side clear and reversing the early momentum, Priestland put the hosts on the board with a penalty after seven minutes.
Scarlets were handed the chance to double the lead eight minutes later, after the visiting front row stood up in the scrum, but Frazier Climo's halfway-line effort struck the post.
Rhys Webb led the Ospreys fightback, sending a neat low kick into the hosts' 22 but full-back Liam Williams collected and ran his side out of immediate danger, before Biggar sent a 35-yard drop-goal wide.
Williams was then on hand again to bail out Scarlets, picking up a chip-kick deep in the corner and sending a perfect clearance into the opposition half, bouncing into touch.
Ospreys trailed but continued to attack with more intensity, Biggar orchestrating waves of pressure, but stern defending and sloppy handling undid much of the good work.
It wasn't until 36 minutes that they earned the opportunity to draw level, when Biggar pointed to the posts from halfway, but the penalty fell short and left and Scarlets went into the break ahead.
It took just a minute of the second-half for Ospreys to earn another penalty but Biggar missed his second of the afternoon, this time a far simpler effort.
Visiting attacks continued to fall flat as a string of handling errors gave Scarlets possession but when it was their turn to burrow into the Ospreys' 22 there was no way through.
Priestland finally added three more points, after 49 minutes, following an infringement in the lineout from Ospreys second row Alun Wyn Jones.
And the game burst into life shortly before the hour mark, as Ospreys got the ball out wide to Dirksen and his diving effort prompted a lengthy deliberation from the TMO.
The wing launched himself at the corner, under pressure from two Scarlets defenders, and he was adjudged to have slipped narrowly into touch on his way to the line.
Shortly after taking to the pitch Rhodri Jones was penalised for not rolling away and Biggar had a third bite of the cherry, eventually getting his side on the board.
Ospreys did eventually touch down five minutes from time, when Biggar's inch-perfect kick set the pack up to drive towards the line and Evans bundled over - Biggar added the conversion.
Priestland responded by kicking Scarlets back into the visitors' half and waves of pressure saw the visitors concede a string of penalties, which resulted in man-of-the-match Jones being sent to the sin bin.
The hosts kicked for the line once more, needing a try to win it, but the 14 men held firm in a resilient display of aggression.
Pens: Priestland 2
Yellow card: Alun-Wyn Jones (Ospreys, 79)
Scarlets: 15 Liam Williams, 14 Kristian Phillips, 13 Nick Reynolds, 12 Scott Williams, 11 Frazier Climo, 10 Rhys Priestland, 9 Gareth Davies, 8 Rob McCusker (captain), 7 John Barclay, 6 Aaron Shingler, 5 George Earle, 4 Jake Ball, 3 Samson Lee, 2 Ken Owens, 1 Phil John.
Replacements: 16 Emyr Phillips, 17 Rob Evans, 18 Rhodri Jones, 19 Richard Kelly, 20 John Snyman, 21 Rhodri Williams, 22 Aled Thomas, 23 Gareth Maule.
Ospreys: 15 Sam Davies, 14 Hanno Dirksen, 13 Ashley Beck, 12 Ben John, 11 Jeff Hassler, 10 Dan Biggar, 9 Rhys Webb, 8 Ryan Jones, 7 Sam Lewis, 6 Joe Bearman, 5 James King, 4 Alun Wyn Jones (captain), 3 Adam Jones, 2 Richard Hibbard, 1 Duncan Jones.
Replacements: 16 Scott Baldwin, 17 Marc Thomas, 18 Aaron Jarvis, 19 Ian Evans, 20 Morgan Allen, 21 Tyler Ardron, 22 Tito Tebaldi, 23 Tom Isaacs.
Referee: Leighton Hodges (Wales)
Assistant Referees: Sean Bricknell, Wayne Davies (both Wales)
TMO: Tim Hayes (Wales)
Edinburgh 16-20 Glasgow Warriors
Stuart Hogg's second-half score dished out a Boxing Day sucker punch to Edinburgh as Glasgow Warriors took away the spoils by 20-16 at Murrayfield.
The 1872 Cup has been won by Glasgow eight times since 2008 and again they continued to get the better of their Scottish opponents after Hogg collected an Alex Dunbar chip.
Edinburgh had held on to the lead for over an hour as Dougie Fife crashed over in a first 40 that saw three sin bins - two for the Warriors to the hosts' one.
Duncan Weir also had his say in Glasgow's victory, winning his personal kicking battle up against Greig Laidlaw by 15 points to 11.
The Warriors had been a menace on the road this season - with five successive Pro12 away victories - and were the first to put points on the board on a boggy Murrayfield pitch.
Weir drilled through a penalty from halfway with three minutes gone but Edinburgh set about pummelling Glasgow's defence with a forwards drive.
Having won a penalty from an eventual scrum, scrum-half Laidlaw had a simpler task in slotting home his side's first three points from ten metres out.
As soon as Edinburgh replied, however, feet off the ground allowed Weir to stretch his legs again and retake the lead for Gregor Townsend's men.
On the quarter-hour mark, the home side worked the ball to the right corner before Jack Cuthbert popped the ball back into the grateful hands of Fife.
The wing crashed over the whitewash to score in arguably the game's first flowing move - Laidlaw making no mistake with the extras.
Weir did not look like missing each time the kicking tee was brought out and the 22-year-old chopped the lead down to one point when Edinburgh were drawn offside.
Shortly after Tyrone Holmes earned himself a yellow card for tackling a man without the ball while off his feet and Edinburgh were gifted the opportunity to restore a four-point advantage - which Laidlaw duly did.
The hosts were set on piling further misery on the Warriors in Holmes' absence and kicked a penalty to touch after a ferocious rolling maul, but Glasgow held firm.
Tensions were rising and after an altercation involving opposing backs Tom Brown and Hogg, both were sent to the sin bin five minutes before half-time.
Edinburgh were finding acres of space amid a depleted Warriors line and would have found their second try but for Cuthbert's crucial fumble a metre away from the try-line.
Play was called back for a penalty and Laidlaw did the honours for Alan Solomons' troops, but they headed into the interval knowing several try-scoring opportunities had gone astray.
However, the home side emerged for the second half showing the exact same attacking verve as Fife - and then David Denton after play was spread from right to left - were hauled down with the try-line looming.
With 15 men back on the pitch for both sides Hogg in particular was eager to make up for lost time, slipping his way through enemy lines to set Glasgow up ten metres away from the whitewash.
Another costly error at the vital moment put a halt to a try - this time Weir with the wayward pass - though the fly-half returned to stroke through a fourth penalty of the afternoon.
Laidlaw came up just short on the halfway line with a penalty effort of his own but Edinburgh were looking the most likely to grab the all-important second try.
But another period of pressure came and went for the hosts and when Nick De Luca was caught offside, Weir snuck through a long-range penalty with room to spare - dragging Glasgow back to within one point.
The home side roared back and Cornell Du Preez was smothered inches away from the line after misdirection from Laidlaw at the ruck.
One moment of magic was to turn the game on its head on 67 minutes as Scotland international Hogg stormed through to latch onto the end of a perfectly-weighted chip from Dunbar.
Weir skewed the conversion wide but with Edinburgh reeling, the visitors expertly saw the game out by controlling much of the possession in the closing stages.
Pens: Laidlaw 3
Pens: Weir 5
Yellow cards: Tyrone Holmes (Glasgow Warriors, 27), Tom Brown (Edinburgh, 36), Stuart Hogg (Glasgow Warriors, 36)
Edinburgh: 15 Jack Cuthbert, 14 Dougie Fife, 13 Nick De Luca, 12 Ben Atiga, 11 Tom Brown, 10 Greig Tonks, 9 Greig Laidlaw (captain), 8 Dave Denton, 7 Roddy Grant, 6 Cornell du Preez, 5 Ollie Atkins, 4 Grant Gilchrist, 3 WP Nel, 2 Ross Ford, 1 Wicus Blaauw.
Replacements: 16 Aleki Lutui, 17 Alex Allan, 18 Geoff Cross, 19 Izak van der Westhuizen, 2 Mike Coman, 21 Grayson Hart, 22 Tony Fenner, 23 Sam Beard.
Glasgow Warriors: 15 Sean Maitland, 14 Tommy Seymour, 13 Stuart Hogg, 12 Alex Dunbar, 11 DTH van der Merwe, 10 Duncan Weir, 9 Chris Cusiter (captain), 8 Ryan Wilson, 7 Tyrone Holmes, 6 Robert Harley, 5 Tom Ryder, 4 Tim Swinson, 3 Jon Welsh, 2 Pat MacArthur, 1 Ryan Grant
Replacements: 16 Dougie Hall, 17 Gordon Reid, 18 Moray Low, 19 Leone Nakarawa, 20 Josh Strauss, 21 Chris Fusaro, 22 Henry Pyrgos, 23 Ruaridh Jackson
Referee: Neil Paterson (Scotland)
Assistant Referees: David Changleng, Bob Nevins (both Scotland)
TMO: Jim Yuille (Scotland)
Newport Gwent Dragons 22-16 Cardiff Blues
There was no Christmas hangover at Rodney Parade as Jason Tovey led Newport Gwent Dragons to a 22-16 victory over Cardiff Blues in a breathless Boxing Day derby.
The fly-half kicked 17 points to lay the foundations while the magnificent Toby Faletau roared through for a score midway through the first half.
The Blues did respond through Kristian Dacey but Tovey's boot told after the break, Leigh Halfpenny's 11 points from the kicking tee proving in vain.
The Welsh rivals headed into the fixture in need of a remedy for their Pro12 form, having both won just one of their last five clashes in the tournament.
The hosts drew first blood, Tovey rounding off a blistering start by knocking a penalty between the posts with just two minutes on the clock.
And the Dragons were not about to take their foot off the pedal with a succession of scything breaks through a shell-shocked Blues line, Dan Evans going the closest to converting pressure into points.
It was on 16 minutes that the screw well and truly turned after Faletau snuck round the front of a Dragons lineout and collected the ball to canter home unchallenged - Tovey adding the extras.
Another scintillating passage of play, this time an interchange between Evans and Hallam Amos, nearly saw the latter run the whole length of the pitch but his chip over the last of the Blues' defences was overhit.
The visitors hauled themselves back into the game in a blink of the eye after hooker Dacey showed a remarkable turn of pace to burst through the tackles and dot down, finishing a move engineered by Halfpenny.
But Evans was again causing havoc and deep into Blues territory managed to offload the ball to partner-in-crime Amos before hitting the turf - only for the teenage wing to be dragged into touch at the last.
For all of the home side's attacking intent the Blues were looking dangerous in their rare moments of possession as Robin Copeland's pick and go gained crucial yardage.
A penalty was eventually called and Halfpenny nailed his first chance of the match to tie the scores at the break and leave the Dragons ruing their profligacy.
A wonderfully-worked move - that would have seen home side centre Ashley Smith touch down - was crossed off the scoresheet shortly after the break as the TMO adjudged that Netani Talei was guilty of obstruction in the build-up.
Then Halfpenny, who was slowly becoming more influential in the game, was handed his second chance from the tee and obliged to hand the visitors the lead for the first time.
Mistakes were creeping into the game from both sides and this time the Dragons benefitted from ill-discipline at the breakdown, Tovey smashing over a penalty to lock up the scores once more.
Almost immediately after Pat Leach found a huge hole in the Blues' line and Tovey clocked his third penalty of the game when lock Macauley Cook was caught offside.
The visitors were beginning to show signs of weariness and things were made worse when Copeland was the recipient of a yellow card following another infringement by a Blue.
And, pinned back in their own territory, they were penalised for blocking to allow Tovey to kick through a simple effort on the hour mark.
In a matter of moments the 24-year-old was on hand to slot through his fifth of the evening, Phil Davies' men being forced into errors after being pushed back behind the gainline.
Halfpenny finally got the opportunity to reduce the arrears with a penalty of his own as the away side sensed hope with ten minutes to go.
Lloyd Williams' show and go exploited a chink in the Dragons' armour but confusion at the breakdown brought the promise to a halt, while Gavin Evans also failed to haul the ball in with space ahead of him.
The Blues jabbed away deep into the Dragons' half but a crucial turnover allowed the hosts to kick away from the danger zone to see the game out.
For Newport Gwent Dragons:
Pens: Tovey 5
For Cardiff Blues:
Pens: Halfpenny 3
Yellow card: Robin Copeland (Cardiff Blues, 55)
Newport Gwent Dragons: 15 Daniel Evans, 14 Will Harries, 13 Pat Leach, 12 Ashley Smith, 11 Hallam Amos, 10 Jason Tovey, 9 Wayne Evans, 8 Toby Faletau, 7 Lewis Evans, 6 Netani Talei, 5 Cory Hill, 4 Andrew Coombs (captain), 3 Nathan Buck, 2 T Rhys Thomas, 1 Owen Evans
Replacements: 16 Sam Parry, 17 Aaron Coundley, 18 Francisco Chaparro, 19 Rob Sidoli, 20 Nic Cudd, 21 Richie Rees, 22 Steffan Jones, 23 Ross Wardle
Cardiff Blues: 15 Leigh Halfpenny, 14 Alex Cuthbert, 13 Gavin Evans, 12 Dafydd Hewitt, 11 Dan Fish, 10 Rhys Patchell, 9 Lloyd Williams, 8 Robin Copeland, 7 Josh Navidi, 6 Macauley Cook, 5 Filo Paulo, 4 Chris Dicomidis, 3 B Bourrust, 2 Kristian Dacey, 1 Sam Hobbs (captain)
Replacements: 16 Rhys Williams, 17 Thomas Davies, 18 Scott Andrews, 19 Ellis Jenkins, 20 Rory Watts-Jones, 21 Lewis Jones, 22 Gareth Davies, 23 Richard Smith
Referee: Ian Davies (Wales)
Assistant Referees: Neil Hennessey, Jon Mason (both Wales)
TMO: Derek Bevan (Wales)