A place in the Guinness PRO12 semi-finals will hang in the balance when Ospreys welcome Ulster to Liberty Stadium on Saturday afternoon.

The Welsh side remain in the top four despite losing their last three league games, while their Irish opponents sit just one point below them after a narrow loss to Munster earlier this month.

What’s at stake?

Ospreys have a tough end to the season, taking on third-placed Scarlets next weekend, but a bonus-point win on Saturday would secure their semi-final spot.

The Welsh region have not lost four in a row in the Guinness PRO12 since their first season in the competition – 2003/04 – but have only won one of their last six games against Irish provinces.

Ulster cross the Irish Sea looking for the four points that would move them above their Welsh opponents, before they face leaders Leinster in their final game of the regular season.

Ulster made it within touching distance of the top four after winning six straight games earlier in the year, but their streak run was ended by Cardiff Blues and now the province must fight for its play-off place.

Ospreys team news: Steve Tandy has named a strong side for Saturday’s showdown, with captain Rhys Webb pairing up with fellow Wales international Dan Biggar.

Tom Habberfield covers the left wing, with Keelan Giles on the right and Kieron Fonotia and Ashley Beck in midfield, while Dan Evans remains at full-back.

In the pack, the front row of Nicky Smith, Scott Baldwin and Brian Mujati is unchanged from last week and Tyler Ardron replaces Rory Thornton in the second row, working alongside Bradley Davies.

James King moves back to number eight this week and Sam Underhill comes in at blindside flanker with Justin Tipuric at openside once more.

Ulster team news: Les Kiss makes three changes with the recently returned Stuart McCloskey starting at inside centre, with Luke Marshall outside him.

Irish international Craig Gilroy comes into the starting XV at full back, joining up with Charles Piutau and captain Andrew Trimble in the back three.

Paddy Jackson is at fly-half and Ruan Pienaar provides the link between the pack and the backline.

Up front, Robbie Diack is brought in at number eight, with Iain Henderson and Sean Reidy joining him in the back row.

Kieran Treadwell and Alan O’Connor will continue their second row partnership for the fifth game in a row, while the front row of Andy Warwick, Rory Best and Wiehahn Herbst is also retained.

Talking points

Ospreys head coach Steve Tandy underlined the importance of this fixture on his side’s play-off chances.

“We’re at that point now where we are effectively playing knock-out, play-off rugby already,” he said.

“Everybody knows that the last month or so hasn’t been what we’ve wanted, but it’s important to remember that what we’ve done before that means we are still in fourth place and in control of our own destiny.

“Of course, that counts for nothing if we don’t deliver on the pitch over the next couple of weekends.

“They’ll believe they can win and they’ll be looking to knock us out.

“We’ve got to prepare for that, we’ve got to not just match them from the first whistle, we’ve got to be prepared to fight for everything, right to the end. They won’t come here and just allow us to have it our own way.

“There’s so much at stake over the next two weekends but we can’t look any further ahead than Ulster at the Liberty, where we have the support behind us to help us make the most of home advantage.”

Lions watch

Ospreys have three Lions in their staring XV compared to Ulster’s two as half-back pairing Rhys Webb and Dan Biggar take to the field with flanker Justin Tipuric.

Both of Ulster’s Lions can be found in the pack: hooker Rory Best prepares for his second tour, while Iain Henderson will be pulling on the red jersey for the first time in June.

Key battle: Dan Biggar v Paddy Jackson

Two experienced international fly-halves will face off on Saturday, with Welshman Dan Biggar pitted against Ulster’s Paddy Jackson.

Ospreys will be buoyed by the return of their key playmaker, whose performances in the RBS 6 Nations earnt him a place in the British & Irish Lions.

Jackson has displayed excellent composure for both his province and country, scoring 94 points in ten appearances for Ulster this season.

Key stat
The Ulstermen have lost just one of their last eight fixtures against Welsh regions: 13-16 in Llanelli in round 13.

Did you know? Ulster’s only defeat in their last seven matches against Ospreys was 20-31 at Liberty Stadium in December 2014.

Ospreys top points scorer: Sam Davies 106pts. Top try scorers: Dan Evans 6
Ulster top points scorer: Ruan Pienaar 100pts. Top try scorer: Jacob Stockdale 8

Overall Guinness PRO12 head to head record:
Played 27, Ospreys won 13, Ulster won 14.

At Liberty Stadium, 3pm – Live on BBC NI & Sky Sports
Referee: John Lacey (IRFU, 63rd competition game)
Assistant Referees: George Clancy (IRFU), Ben Whitehouse (WRU)
Citing Commissioner: Dennis Jones (WRU)
TMO: Neil Paterson (SRU)