Munster pulling out a four point lead at the top of the table
The focus returns once again to the PRO12 after two weeks of European competition, with Irish Provinces topping three of the six European Cup Pools.
Ulster are the stand-out performers so far, the only team with a 100 per cent winning record still left in the competition, garnering 18 pool points in the process.
Munster and Leinster, both also past winners of the trophy, top their respective pools, whilst Cardiff Blues, the top placed Welsh Region, are only two points shy of their pool leaders, reigning champions Toulon.
The Irish provinces are faring well in the PRO12 as well, with three of the four play-Off places taken up by them, Munster pulling out a four point lead at the top of the table as the half-way point of the season approaches.
They are in action at Musgrave Park on Saturday evening when they face Scarlets, the Welsh region having won at this venue last time they visited.
The round starts off on Friday night with the remaining three teams currently in the play-Off zone - Leinster, Glasgow Warriors and Ulster - all in action.
Second placed Leinster travel to Murrayfield buoyed by the fact they have won their last five contests with Edinburgh, whilst in Glasgow, Treviso are the visitors.
Having led in the early part of the season Warriors now reside in third place in the table, level on points with Ulster and need a win to keep their season on track.
The remaining top-four team, Ulster, will be looking to maintain their near perfect record against Italian teams when Zebre run out at Ravenhill.
We look at all the weekend's matches:
Friday, December 20
Cardiff Blues v Ospreys
(Cardiff Arms Park - Kick-off: 19.05; 19.05 GMT)
Cardiff Blues only defeat in their last five games in all tournaments was 10-31 at home to Munster in the PRO12 on November 23.
The Blues have not beaten a fellow Welsh Region, excepting the Dragons, since Ospreys visited the Cardiff City Stadium on New Year’s Eve 2010.
Ospreys have won just two of their last five PRO12 encounters, at home to both Dragons and Zebre. Ospreys have been defeated in their last four away games in all competitions since they visited Connacht in the PRO12, on September 28.
Ospreys have won their last nine PRO12 fixtures against fellow Welsh Regions since losing 20-21 to the Dragons at Rodney Parade on 6th January 2012.
The Blues have already defeated Ospreys this season in the Anglo-Welsh Cup at Liberty Stadium, but in the PRO12 have not won against their rivals since 31st December 2010.
Cardiff Blues: 15 Leigh Halfpenny, 14 Alex Cuthbert, 13 Richard Smith, 12 Dafydd Hewitt, 11 Harry Robinson, 10 Gareth Davies, 9 Lloyd Williams, 8 Robin Copeland, 7 Rory Watts-Jones, 6 Andries Pretorius, 5 Filo Paulo, 4 Macauley Cook, 3 Benoit Bourrust, 2 Kristian Dacey, 1 Sam Hobbs (captain).
Replacements: 16 Rhys Williams, 17 Thomas Davies, 18 Scott Andrews, 19 James Down, 20 Josh Navidi, 21 Lewis Jones, 22 Gavin Evans, 23 Chris Czekaj.
Ospreys: 15 Sam Davies, 14 Hanno Dirksen, 13 Tom Isaacs, 12 Ben John, 11 Aisea Natoga, 10 Dan Biggar, 9 Tom Habberfield, 8 Joe Bearman, 7 Justin Tipuric, 6 Sam Lewis, 5 James King, 4 Alun Wyn Jones (captain), 3 Adam Jones, 2 Scott Baldwin, 1 Ryan Bevington.
Replacements: 16 Matthew Dwyer, 17 Marc Thomas, 18 Dan Suter, 19 Morgan Allen, 20 Tyler Ardron, 21 Tito Tebaldi, 22 Ashley Beck, 23 Jeff Hassler.
Referee: Jérôme Garcès (France)
Assistant referees: Rhys Thomas (Wales), Sean Brickell (Wales)
TMO: Gareth Simmonds (Wales)
Edinburgh v Leinster
(Murrayfield - Kick-off: 19.35; 19.35 GMT)
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 Al Dickinson.
Replacements: 16 Aleki Lutui, 17 Wicus Blaauw, 18 Geoff Cross, 19 Sean Cox, 20 Mike Coman, 21 Grayson Hart, 22 Tony Fenner, 23 Sam Beard.
Leinster: 15 Zane Kirchner, 14 Darragh Fanning, 13 Brian O'Driscoll, 12 Noel Reid, 11 Luke Fitzgerald, 10 Ian Madigan, 9 Isaac Boss, 8 Jordi Murphy, 7 Shane Jennings, 6 Kevin McLaughlin, 5 Tom Denton, 4 Leo Cullen (captain), 3 Martin Moore, 2 Aaron Dundon, 1 Michael Bent.
Replacments: 16 James Tracy, 17 Jack O'Connell, 18 Tadhg Furlong, 19 Quinn Roux, 20 Dominic Ryan, 21 John Cooney, 22 Jimmy Gopperth, 23 Brendan Macken.
Referee: Peter Fitzgibbon (Ireland)
Assistant referees: Andrew Mcmenemy (Scotland), Adrian Graves (Scotland)
TMO: Iain Ramage (Scotland)
Glasgow Warriors v Treviso
(Scotstoun Stadium - Kick-off: 19.35; 19.35 GMT)
Glasgow Warriors have slipped to two defeats in their last four PRO12 fixtures, dropping them from top of the table to third.
The Warriors won ten successive home games at Scotstoun between December 2012 and October 2013, however since then they have lost their last three matches at the venue in all tournaments.
The Scotsmen have been victorious in their last eight contests with Italian opponents since Treviso won 15-13 at Firhill on 23rd September 2011.
Benetton Treviso are winless in their last four PRO12 encounters since beating Connacht 23-3 at Stadio Monigo in Round Five, although they did draw 26-all at home to Cardiff Blues last time out.
The Italians have won only one away game in any competition in 2013: 41-17 at the Scarlets in the PRO12 in Round 22 last season.
Treviso’s most recent victory in Scotland came against Edinburgh at Murrayfield in October 2012.
Glasgow have won their last three matches against Treviso since the Italians victory at Firhill in September 2011
Glasgow Warriors: TBC
Referee: Claudio Blessano (Italy)
Assistant referees: David Changleng (Scotland), Bob Nevins (Scotland)
Ulster v Zebre
(Ravenhill - Kick-off: 19.05; 19.05 GMT)
Ulster’s only loss in their last eleven fixtures in all tournaments was 9-17 at the Scarlets in the PRO12 on November 2.
The Ulstermen have lost just once at home since early February: 12-13 to Glasgow Warriors in Round Two of the PRO12.
Ulster have met Italian opposition on 24 previous occasions in all competitions and lost only once: 12-23 at home to Treviso in the PRO12 in October 2011.
Zebre are winless in their last ten contests in all tournaments since beating Cardiff Blues at the Arms Park in Round Three of the PRO12, although they did draw 16-all with Scarlets in Parma on October 25.
The two sides have met on three previous occasions with Ulster victorious in each instance, including a 19-11 win in Parma.
Ulster: 15 Ricky Andrew, 14 Craig Gilroy, 13 Jared Payne, 12 Paddy Wallace, 11 Michael Allen, 10 James McKinney, 9 Ruan Pienaar, 8 Robbie Diack, 7 Sean Doyle, 6 Mike McComish, 5 Lewis Stevenson, 4 Johann Muller (captain), 3 Ricky Lutton, 2 Niall Annett, 1 Callum Black.
Replacements: 16 Rob Herring, 17 Tom Court, 18 Adam Macklin, 19 Neil McComb, 20 Conor Joyce, 21 Michael Heaney, 22 Peter Nelson, 23 David McIlwaine.
Zebre: 15 Dion Berryman, 14 Leonardo Sarto, 13 Tommaso Iannone, 12 Roberto Quartaroli, 11 Giovanbattista Venditti, 10 Luciano Orquera, 9 Gugliemo Palazzani, 8 Nicola Cattina, 7 Filippo Ferrarini, 6 Filippo Cristiano, 5 Marco Bortolami (captain), 4 Quintin Geldenhuys, 3 Andrea de Marchi, 2 Andrea Manici, 1 Dario Chistolini.
Replacements: 16 Tommaso D'apice, 17 Matias Aaguero, 18 Luca Redofini, 19 Michael van Vuren, 20 Emiliano Caffini, 21 Alberto Chillon, 22 Kameli Ratuvou, 23 Brendon Leonard.
Referee: Neil Hennessy (Wales)
Assistant referees: Sean Gallagher (Ireland), Dermot Blake (Ireland)
TMO: Simon McDowell (Ireland)
Saturday, December 21
Connacht v Newport Gwent Dragons
(The Sportsground - Kick-off: 17.00; 17.00 GMT)
Connacht’s only two victories in their last dozen matches in all tournaments have both been away from home in the European Cup, at Zebre and at Toulouse.
Connacht’s only victory in the PRO12 since April was 25-16 at home to Zebre in Round One this season. Connacht have lost all three games they have played against Welsh opponents this season.
Newport Gwent Dragons only victory in their last four PRO12 fixtures was 23-8 away at Glasgow in Round Eight, this represents their only victory on the road since they beat Zebre in Parma in February.
The Welshmen have lost their last three matches against Irish opponents and have won just once away from home at an Irish Province since 2004: 16-14 over Ulster at Ravenhill in September 2008.
Each side won its respective home game when the two teams met last season, whilst Dragons only previous victory in ten previous visits to the Sportsground came on 1st May 2004.
Newport Gwent Dragons: TBC
Referee: Alain Rolland (Ireland)
Assistant referees: Gary Conway (Ireland), Paul Hancock (Ireland)
Munster v Scarlets
(Musgrave Park - Kick-off: 19.15; 19.15 GMT)
Munster have won their last seven matches in all tournaments since their 23-29 defeat to Edinburgh at Murrayfield in the European Cup on October 12.
The Munstermen top the PRO12 table courtesy of suffering only one reversal so far this season: 19-29 at Treviso in Round Three.
Munster have won all four matches they have played against Welsh Regions this season.
Scarlets only win in their last five matches in all tournaments was 24-21 at Connacht in Round Eight of the PRO12.
That victory in Galway represents the Welshmen’s only success on the road in any competition since November 2012.
Munster won fourteen successive games against the Scarlets between April 2007 and December 2011, but since then are winless in their last three fixtures against the Welshmen. Scarlets won 13-6 when they visited Musgrave Park last season.
Referee: Nigel Owens (Wales)
Assistant referees: David Wilkinson (Ireland), Michael Black (Ireland)
TMO: Dermot Moloney (Ireland)