Munster welcome Ulster to Thomond Park on Saturday, knowing that victory over their interprovincial rivals will book a Guinness PRO12 play-off spot and move them closer to a home semi-final. The Irish derbies are always tasty affairs but with Ulster looking to keep their own top four hopes on track, this one is even more important than most. Both teams are in form – Ulster unbeaten in seven Guinness PRO12 matches and Munster having lost just once in any competition since mid-December – setting Saturday’s clash up as a potential epic. What’s at stake? Munster are currently second in the Guinness PRO12 table, two points behind leaders Leinster, but with a healthy nine-point cushion to Ulster in fifth, a win at Thomond Park would guarantee them a place in the play-offs with two rounds remaining. Perhaps just as importantly, given that no home team has lost a semi-final since they were introduced to the competition, Munster are looking to maintain their seven-point advantage over Ospreys in third. Ulster have just as much on the line, level on points with fourth-placed Scarlets but outside the play-offs on number of wins. They haven’t lost in the Guinness PRO12 since going down 16-13 to the Llanelli-based outfit back in round 13 and with matches against high-flying Ospreys and Leinster still to come, Les Kiss’ troops can scarcely afford to lose any ground to the Welshmen. Munster team news Perhaps with half an eye on next Saturday’s European semi-final against Saracens, Munster director of rugby Rassie Erasmus makes nine changes to his starting XV. A changed front row sees Dave Kilcoyne, Niall Scannell and John Ryan named, while Donnacha Ryan links up with Billy Holland in the second row. There are two alterations in the back row with only Jack O’Donoghue retained at No.8 as captain Peter O’Mahony and Tommy O’Donnell return to the flanks. The half-back pairing of Duncan Williams and Tyler Bleyendaal remain in situ but Keith Earls, Rory Scannell and Simon Zebo are introduced to the backline with Earls on the left wing, Scannell inside Francis Saili, and Zebo at full-back. Ulster team news Unlike his Munster counterpart, Kiss has opted for continuity in Ulster’s starting XV with shows just three changes from last Friday’s draw with Cardiff Blues. There are two changes in the back three as Jacob Stockdale, Ulster’s top try scorer in the Guinness PRO12 this season, comes in at full-back to replace the injured Jared Payne. Andrew Trimble, who made his return from a hand injury in a second-half appearance last weekend, is preferred to fellow Ireland international Craig Gilroy on the right wing with Charles Piutau retaining the No.11 jersey. Chris Henry is the sole change in the pack as he comes in at openside flanker, with Sean Reidy shifting to No.8 and Iain Henderson continuing at blindside. Talking Points Munster are a formidable force at Thomond Park – have only lost one match at the ground in their last 14 games since December 2015. They have also won three matches on the bounce against fellow Irish provinces but centre Saili has warned his team not to underestimate Ulster, especially an ex-teammate of his in winger Piutau. “I have only played against him once or twice. That was in club rugby back home,” said New Zealander Saili. “It is going to be a good outing against him. “I know how dangerous he is and leading into this weekend, reviewing against Ulster, he is going to be one of the main targets to keep an eye on. “Charles is someone I played with through the grades and back home in the Super Rugby franchise and the All Blacks as well, so it is interesting to play against him. But like I have always said, once you cross that line, you have no friends on the field. “A guy like Charles sniffs out opportunities. With us we need to trust our defence systems and I know we have been doing that the whole year.” Meanwhile, Ulster lock Alan O’Connor is expecting a tough, physical battle at Thomond Park. “We have to man up to them or they will take you for a walk,” said O’Connor. “There are a good, all-round pack, they have good ball carriers, they have a good set-piece and we just have to beat them at what they are good at and what we are good at. We have to make sure we’re on the gain-line in attack and defence. “Whatever team they put out they will be buzzing and it will be a tough hard one.” Lions contenders This is the final chance for players to make a case to tour with The British & Irish Lions this summer as coach Warren Gatland names his squad next week. 2013 Lion Simon Zebo will be targeting a strong performance from full-back, as will another Munster man who has previously pulled on the Lions jersey, winger Keith Earls. Front-rower John Ryan, second row Donnacha Ryan and flanker Peter O’Mahony will also want to make Gatland sit up and take notice in two hotly-contested positions. Ulster hooker Rory Best is considered a candidate to captain the Lions, while Iain Henderson, winger Andrew Trimble and fly-half Paddy Jackson could all put themselves in the mix with a timely display. Key Battle: Peter O’Mahony v Iain Henderson A pair of Ireland team-mates will do battle in the back row at Thomond Park and whichever can control the breakdown could well lead their side to victory. Peter O’Mahony was a last-minute inclusion for Ireland’s final game of the RBS 6 Nations, winning man of the match in the 13-9 win over England after coming in for Jamie Heaslip. Ireland’s only try that day was scored by Iain Henderson, starting in the second row, but he will line up in the No.6 jersey for Ulster, up against Munster skipper O’Mahony. With competition for Lions places so tight in both the second row and the back row, as well as Guinness PRO12 semi-final spots on the line, there is a lot at stake in this match-up. Did You Know? Ulster have won just one of their last five fixtures against fellow Irish provinces: 23-7 at home to Connacht in round 11. Key stat Munster are unbeaten in their last five encounters with Ulster since the Ulstermen’s 19-17 victory at Thomond Park in May 2014. Munster top points scorer: Tyler Bleyendaal – 115. Top try scorer: Ronan O’Mahony – 9 Ulster top points scorer: Paddy Jackson – 74. Top try scorer: Jacob Stockdale – 8 Overall Guinness PRO12 head to head record: Played 30, Munster won 16, Ulster won 13 with 1 game drawn. At Thomond Park, 3pm Live on Sky Sports Referee: Marcus Mitrea (FIR, 65th competition game) Assistant Referees: Emanuele Tomo (FIR), John Carvill (IRFU) Citing Commissioner: Eddie Wigglesworth (IRFU) TMO: Stefano Penne (FIR)