Ospreys welcome Leinster to the Liberty Stadium on Saturday as the two title contenders do battle in Round 19 of the Guinness PRO12. Leinster approach the game full of confidence after a win over Wasps in the quarter-final of the European Champions Cup last weekend. But hosts Ospreys will look to rediscover some form after crashing out of the Challenge Cup with a loss to Stade Français as Dan Biggar becomes the youngest player to reach 200 caps for the club. What’s at stake? A win in Wales could bring Ospreys level with Munster – who were the last team to beat Steve Tandy’s men at Liberty Stadium back in February – and closer to earning a home semi-final. Despite last weekend’s Challenge Cup disappointment Ospreys, currently the leading Welsh side in the Guinness PRO12, look set to qualify for the Champions Cup next season. League-leaders Leinster are yet to lose a game in 2017, but face a tough run of games against Connacht, Glasgow and Ulster after their battle in Swansea. And the Irish province can maintain their lead at the top with a win. Ospreys team news: Steve Tandy only made two changes to the starting XV which lost out to Stade Français last weekend, with Kieron Fonotia stepping in for Ashley Beck at outside centre and Olly Cracknell coming into the pack for Sam Underhill. Rhys Webb captains the side at scrum half as he makes his 100th Guinness PRO12 appearance, linking up with fly-half Dan Biggar as he steps out in an Ospreys shirt for the 200th time. Dan Evans and Keelan Giles remain on the wing, with Josh Matavesi in the centre and Sam Davies at full-back. An unchanged front row of Nicky Smith, Scott Baldwin and Brian Mujati will pack down in front of locks Lloyd Ashley and Rory Thornton with Alun Wyn Jones still unavailable due to injury. Olly Cracknell is given the chance to start on the blindside and joins Dan Baker and Justin Tipuric in the back row. Leinster team news: The major changes come in the backline for Leinster, with captain Isa Nacewa taking Joey Carbery’s place at full-back as the 21-year-old returns to fly-half for the first time since February. Fergus McFadden gets his fifth start of the season on the left wing as Rory O’Loughlin moves to the right to replace an injured Adam Byrne. Sean Cronin returns at hooker after injuring his hamstring in January with Jack McGrath and Tadhg Furlong either side, as Mike Ross awaits his 150th Leinster appearance from the bench. Mick Kearney moves into the second row with Devin Toner and Jack Conan remains in the back row, but this week is joined by Rhys Ruddock and Josh van der Flier. Talking points Ospreys head coach Steve Tandy was disappointed with the loss to Stade Français, but his side are now looking to the task at hand. “There’s been a lot of soul searching at the start of the week and some pretty difficult questions being asked, but as the week has gone on we’ve had to put that behind us and focus on the challenges ahead of us,” he said. “I don’t think there’s a bigger challenge in European rugby this season than Leinster, but this group has to step up and show what they’re about. “It’s as much a test of character as it is of ability, but we know that this is a proud group capable of performing to a much higher standard than they achieved in the last two games.” Key battle: Dan Biggar v Joey Carbery Carbery’s sublime performance at full-back earned him man-of-the-match last weekend, but this week he returns to fly-half for the first time in four games. The 21-year-old Irishman will face one of the most impressive and challenging fly-halves in the Guinness PRO12 in Welsh international Dan Biggar. Biggar, 27, has significantly more experience than his Irish counterpart but Carbery has displayed incredible attacking instincts in recent weeks, setting up Nacewa’s try against Wasps with a perfect offload. Lions Watch Up front, Leinster props Tadhg Furlong and Jack McGrath may have done enough to make it onto a plane to New Zealand along with Ospreys flanker Justin Tipuric. With Conor Murray and Greig Laidlaw not yet back to club rugby after sustaining injuries in the RBS 6 Nations, Ospreys’ Rhys Webb will look to use every possible opportunity to impress Warren Gatland at scrum-half. For Leinster, Robbie Henshaw has been tipped by many as worthy of one of the hotly-contested centre spots. Key stat Leinster’s only defeat to Ospreys since November 2012 was 19-25 at Liberty Stadium in the Guinness PRO12 in April 2014. Did you know? The Leinstermen have been defeated just once in their last nine fixtures against Welsh regions – on their visit to Scarlets in round 9. Overall Guinness PRO12 head to head record: Played 29, Ospreys won 11, Leinster won 15, with 3 games drawn. At Liberty Stadium, 3pm. Live on Sky Sports Referee: John Lacey (IRFU, 62nd competition game) Assistant Referees: David Wilkinson (IRFU), Rob Price (WRU) Citing Commissioner: John Charles (WRU) TMO: Neil Paterson (SRU)