We look at all the Round Nine action
With the completion of their postponed Round Four game against Zebre, Ulster have now pulled out a six-point lead at the top of the Pro12 table.
They are in action in Italy again on Friday, when they face Benetton Treviso at Stadio Monigo, and will be looking to extend their unbeaten record in the country as well as maintaining their 100 percent start to this season's Pro12.
Current Pro12 champions, Ospreys, are also in action on Friday travelling to Murrayfield to play Edinburgh Rugby. Ospreys sit just outside the top four due to poorer points difference than Munster, should results go their way this weekend it could be the first time they have entered the play-off zone this season.
The match of the day must be the encounter at Scotstoun where third placed Glasgow Warriors must overcome the reigning European champions, Leinster if they are to set a new Warriors record in this tournament of seven successive wins.
The final game on Friday is in Wales when Newport Gwent Dragons host Connacht. Both teams have had a mixed start to their seasons, and a win would be a welcome boost to their campaigns.
The round concludes with two games on Sunday, Munster v Scarlets and Zebre v Cardiff Blues. After having narrowly missed out to Ulster last weekend, Zebre are still looking for their first win in the completion, and will be hoping Blues poor form continues for one more week.
Munster will be hoping their impressive record against Scarlets in Ireland will continue, they have not lost to the Welsh Region since March 2007, whilst second placed Scarlets will be aiming to close the gap on leaders Ulster.
We look at all the Round Nine action!
Friday, November 23
BENETTON TREVISO v ULSTER
(Stadio Monigo - 19.05; 18.05 GMT)
Benetton Treviso have slipped to four straight defeats in all competitions since their 27-22 victory over Edinburgh at Murrayfield on 5 October. Treviso have lost their last seven encounters with Irish provinces.
Ulster very nearly lost their 100% record this season when they narrowly overcame Zebre 27-25 in a rearranged Pro12 encounter at Parma on Sunday.
The Ulstermen have won their last five away games and have never lost in nine previous visits to Italy in all competitions.
The two sides have met on eight previous occasions with Ulster's only defeat being 23-12 at Ravenhill in October 2011.
Treviso: 15 Brendan Williams, 14 Giulio Toniolatti, 13 Christian Loamanu, 12 Andrew Vilk, 11 Ludovico Nitoglia, 10 Alberto Di Bernardo, 9 Fabio Semenzato, 8 Marco Filippucci, 7 Paul Derbyshire, 6 Valerio Bernabò, 5 Corniel Van Zyl (captain), 4 Marco Fuser, 3 Jacobus Roux, 2 Franco Sbaraglini, 1 Matteo Muccignat.
Replacements: 16 Enrico Ceccato, 17 Giovanni Maistri, 18 Ignacio Fernandez-Rouyet, 19 Filippo Giusti, 20 Andrea Pratichetti, 21 Angelo Esposito, 22 James Ambrosini, 23 Luca Morisi.
Ulster: 15 Peter Nelson, 14 Andrew Trimble, 13 Jared Payne, 12 Paddy Wallace, 11 Michael Allen, 10 Niall O'Connor, 9 Paul Marshall, 8 Roger Wilson (captain), 7 Mike McComish, 6 Nick Williams, 5 Nigel McComb, 4 Robbie Diack, 3 Declan Fitzpatrick, 2 Rob Herring, 1 Tom Court.
Replacements: 16 Nigel Brady, 17 Callum Black, 18 John Afoa, 19 James Simpson, 20 Ali Birch, 21 Michael Heaney, 22 Stuart Olding, 23 Chris Cochrane.
Referee: Peter Allan (Scotland)
Assistant Referees: Andrea Spadoni, Stefano Traversi (both Italy)
TMO: Stefano Marama (Italy)
EDINBURGH v OSPREYS
(Murrayfield - 19.05; 19.05 GMT)
Edinburgh have lost their last seven encounters in all competitions since overcoming Zebre 41-10 at Murrayfield in the Pro12 on 14 September. Edinburgh's only win over a Welsh region in their last four such fixtures was 21-19 over Cardiff Blues at the Arms Park on 7 September.
Ospreys, the reigning Pro12 champions, have got their defence back on track courtesy of five successive victories in the tournament.
Ospreys have won just one of their last four matches against Scottish opponents.
Ospreys achieved the season's double over Edinburgh in 2011/12, claiming a win at Murrayfield for the first time since 2007 in the process.
Edinburgh: 15 Greig Tonks, 14 Sep Visser, 13 Dougie Fife, 12 James King, 11 Tom Brown, 10 Gregor Hunter, 9 Richie Rees, 8 Stuart McInally, 7 Roddy Grant, 6 Sean Cox (captain), 5 Izak van der Westhuizen, 4 Perry Parker, 3 Willem Nel, 2 Ross Ford, 1 John Yapp.
Replacements: 16 Alun Walker, 17 Allan Jacobsen, 18 Lewis Niven, 19 Robert McAlpine, 20 Hamish Watson, 21 Chris Leck, 22 John Houston, 23 Mike Penn.
Ospreys: 15 Richard Fussell 14 Tom Isaacs, 13 Andrew Bishop, 12 Jonathan Spratt, 11 Eli Walker, 10 Matthew Morgan, 9 Rhys Webb, 8 Joe Bearman (captain), 7 Sam Lewis, 6 George Stowers, 5 James King, 4 Lloyd Peers, 3 Owen Williams, 2 Scott Baldwin, 1 Ryan Bevington.
Replacements: 16 Duncan Jones, 17 Matthew Dwyer, 18 Nicky Thomas, 19 Ian Gough, 20 Morgan Allen, 21 Tom Habberfield, 22 Matthew Morgan, 23 Ross Jones.
Referee: David Wilkinson (Ireland)
Assistant Referees: David Changleng, Adrian Graves (both Scotland)
TMO: Iain Heard (Scotland)
GLASGOW WARRIORS v LEINSTER
(Scotstoun Stadium - 19.35; 19.35 GMT)
Glasgow Warriors are going for a new Warriors record in the history of this competition - seven successive wins.
However Glasgow's only wins in their last nine encounters with Irish provinces have both been over Connacht.
Leinster's four game winning run in all competitions ended at Ospreys in round eight of the Pro12.
The Leinstermen have not been defeated by a team from Scotland since Glasgow won 23-19 at the RDS on 17 September 2011.
The Warriors have lost just once at home to Leinster since 2007: 23-16 in the European Cup at Firhill in January 2012.
Glasgow: 15 Peter Murchie, 14 Tommy Seymour, 13 Alex Dunbar, 12 Peter Horne, 11 DTH Van Der Merwe, 10 Ruaridh Jackson, 9 Sean Kennedy, 8 Josh Strauss, 7 Chris Fusaro (captain), 6 Rob Harley, 5 Tom Ryder, 4 Tim Swinson, 3 Mike Cusack, 2 Pat MacArthur, 1 Gordon Reid.
Replacements: 16 Finlay Gillies, 17 Ofa Fainga'anuku, 18 Moray Low, 19 James Eddie, 20 Ryan Wilson, 21 George Graham, 22 Scott Wight, 23 Byron McGuigan.
Leinster: 15 Isa Nacewa, 14 Dave Kearney, 13 Brendan Macken, 12 Andrew Goodman, 11 Fionn Carr, 10 Ian Madigan, 9 Isaac Boss, 8 Sean O'Brien, 7 Shane Jennings, 6 Kevin McLaughlin, 5 Quinn Roux, 4 Leo Cullen, 3 Jamie Hagan, 2 Aaron Dundon, 1 Jack McGrath.
Replacements: 16 Thomas Sexton, 17 Jack O'Connell, 18 Martin Moore, 19 Devin Toner, 20 Jordi Murphy, 21 John Cooney, 22 Noel Reid, 23 Andrew Conway.
Referee: Neil Hennessey (Wales)
Assistant Referees: Andy Macpherson, Bob Nevins (both Scotland)
TMO: Andy Ireland (Scotland)
NEWPORT GWENT DRAGONS v CONNACHT
(Rodney Parade - 19.00; 19.00 GMT)
Newport Gwent Dragons have slipped to seven straight defeats in all competitions – their worst sequence since the region was formed in 2003.
The Dragons have not overcome an Irish province since beating Ulster 22-9 at Rodney Parade in the Pro12 on 30 September 2011.
Connacht beat Treviso 18-3 in round eight and are attempting back to back Pro12 victories for the first time since April.
Connacht's only away wins in 2012 in all competitions have come at Zebre (twice) and Friday's opponents the Dragons at Rodney Parade in March.
Connacht achieved the season's double over the Men from Gwent in 2011/12.
Dragons: 15 Tom Prydie, 14 Will Harries, 13 Pat Leach, 12 Ashley Smith, 11 Tonderai Chavhanga, 10 Dan Evans, 9 Wayne Evans, 8 Tom Brown, 7 Nic Cudd, 6 Lewis Evans (captain), 5 Rob Sidoli, 4 Adam Jones, 3 Dan Way, 2 Hugh Gustafson, 1 Phil Price.
Replacements: 16 Steve Jones, 17 Owen Evans, 18 Nathan Buck, 19 Ian Nimmo, 20 Ieuan Jones, 21 Jonathan Evans, 22 Lewis Robling, 23 Jack Dixon.
Connacht: 15 Robbie Henshaw, 14 Tiernan O'Halloran, 13 Danie Poolman, 12 Dave McSharry, 11 Gavin Duffy (captain), 10 Dan Parks, 9 Kieran Marmion, 8 Eoin McKeon, 7 Willie Faloon, 6 Andrew Browne, 5 Mick Kearney, 4 Michael Swift, 3 Nathan White, 2 Jason Harris-Wright, 1 Denis Buckley.
Replacements: 16 Ethienne Reynecke, 17 Rodney Ah You, 18 Ronan Loughney, 19 Dave Gannon, 20 Johnny O'Connor, 21 David Moore, 22 Miah Nikora, 23 Matt Healy.
Referee: Giuseppe Vivarini (Italy, 4th competition game)
Assistant Referees: James Jones, Kevin Shorte (both Wales)
Sunday, November 25
MUNSTER v SCARLETS
(Musgrave Park - 17.15; 17.15 GMT)
Munster have won their last three games in all competitions. The Munstermen's only home defeat in the Pro12 since October 2011 was 18-9 to Leinster at Thomond Park on 31 March.
Munster have won their last 15 games at Musgrave Park since Glasgow won there 21-18 on 10 May 2008.
Scarlets have won their last three matches in the Pro12 and are unbeaten in their last four encounters with Irish provinces in the competition.
Munster are unbeaten in their last 15 clashes with Scarlets in all competitions since the European Cup quarterfinal in March 2007. Scarlets have lost on all their seven previous visits to Musgrave Park.
Munster: 15 Felix Jones, 14 Doug Howlett (captain), 13 Casey Laulala, 12 James Downey, 11 Luke O'Dea, 10 Ian Keatley, 9 Duncan Williams, 8 Paddy Butler, 7 Niall Ronan, 6 Dave O'Callaghan, 5 Billy Holland, 4 Ian Nagle, 3 Stephen Archer, 2 Mike Sherry, 1 Wian Du Preez.
Replacements: 16 Damian Varley 17 Marcus Horan, 18 BJ Botha, 19 Dave Foley, 20 CJ Stander, 21 Peter Stringer, 22 JJ Hanrahan, 23 Denis Hurley.
Scarlets: 15 Morgan Stoddart 14 Nick Reynolds, 13 Gareth Maule, 12 Gareth Owen, 11 Andy Fenby, 10 Aled Thomas, 9 Gareth Davies, 8 Craig Price, 7 Johnathan Edwards (captain), 6 George Earle, 5 Richard Kelly, 4 Jake Ball, 3 Jacobie Adriaanse, 2 Emyr Phillips, 1 Phil John.
Replacements: 16 Kirby Myhill, 17 Shaun Hopkins, 18 Samson Lee, 19 Johan Snyman, 20 Dan Thomas, 21 Rhodri Williams, 22 Dan Newton, 23 Adam Warren.
Referee: Laurent Cardona (France)
Assistant Referees: M Patton, Eanna O'Dowd (both Ireland)
TMO: Seamus Flannery (Ireland)
ZEBRE v CARDIFF BLUES
(Stadio XXV Aprile - 15.00; 14.00 GMT)
Zebre came within a whisker of gaining a first ever win in Parma on Sunday in the rearranged fixture with table-topping Ulster, leading 25-20 with just five minutes left, only to concede a converted penalty try.
Cardiff Blues have slipped to four straight defeats in the Pro12 The Blues have won all 14 previous encounters they have played against Italian opponents in all competitions.
The two sides have never met before.
Zebre: 15 David Odiete, 14 Leonardo Sarto, 13 Gonzalo Garcia (captain), 12 Samuele Pace, 11 Sinoti Sinoti, 10 Daniel Halangahu, 9 Tito Tebaldi, 8 Andries Van Schalkwyk, 7 Nicola Cattina, 6 Filippo Ferrarini, 5 Filippo Cazzola, 4 Josh Sole, 3 David Ryan, 2 Andrea Manici, 1 Salvatore Perugini.
Replacements: 16 Carlo Festuccia, 17 Andrea De Marchi, 18 Luca Redolfini, 19 Emiliano Caffini, 20 Filippo Cristiano, 21 Alberto Chillon, 22 Paolo Buso, 23 Ruggero Trevisan.
Cardiff Blues: 15 Dan Fish, 14 Owen Williams, 13 Gavin Evans, 12 Dafydd Hewitt, 11 Tom James, 10 Ceri Sweeney, 9 Lloyd Williams, 8 Robin Copeland, 7 Josh Navidi (captain), 6 Rory Watts-Jones, 5 James Down, 4 Macauley Cook, 3 Taufa'ao Filise, 2 Rhys Williams, 1 Nathan Trevett
Replacements: 16 Marc Breeze, 17 Sam Hobbs, 18 Benoit Bourrust, 19 Michael Paterson, 20 Andries Pretorius, 21 Lewis Jones, 22 Rhys Patchell, 23 Tom Williams.
Referee: Leo Colgan (Ireland)
Assistant Referees: Claudio Blessano, Simone Boaretto (both Italy)
TMO: Mauro Dordolo (Italy)