Ospreys are boosted by the return of captain Alun Wyn Jones for their derby against the Scarlets at the Liberty Stadium on Tuesday.
The inspirational second-row starts alongside Rory Thornton while Dan Baker and Justin Tipuric are also back in the starting XV this week.
Sam Parry returns at hooker and will pack down in the middle of Ma'afu Fia and Nicky Smith, with James King completing their forwards.
Behind them it's the same half-backs that helped thump Grenoble while Josh Matavesi is back at centre and Keelan Giles is on the wing.
Meanwhile, Scarlets head coach Wayne Pivac can call on the services of wing Johnny Mcnicholl for the derby as he returns to fitness.
As McNicholl returns for only his second Scarlets appearance fellow winger DTH van der Merwe moves to the left wing with the remainder of the backline unchanged from the one that started against Toulon at Parc y Scarlets last weekend whilst the pack remains unchanged.
Speaking ahead of the derby clash head coach Pivac said: "They've got some quality right throughout the team, as we have. I think both clubs are in a pretty good space at the moment. It's a mouthwatering clash.
"It went well [at the Liberty] last season but it's a new game, we have to make sure we start well and the set piece goes well so we can play off it.
"Swinging back into the PRO12 it certainly is a massive game. We've got players who play together in the Welsh set-up, both teams know each other inside out. It's certainly one of the biggest games of the season if not the biggest."
Form: Ospreys have won their last five matches in all competitions and in the PRO12 have lost just one of their last five: 0-33 in Munster in Round 8. Ospreys are the best home side in the PRO12 this season having recorded a perfect five maximum point victories. Scarlets have won their last seven PRO12 matches, their best ever run in a single season, and have picked up 24 out of a possible 25 league points from their last five Championship games. Last season each side won at their opponent’s home ground in the PRO12, Scarlets triumphing at Liberty Stadium for the first time since 2007.
Ospreys: 15 Sam Davies, 14 Keelan Giles, 13 Ashley Beck, 12 Josh Matavesi, 11 Dan Evans, 10 Dan Biggar, 9 Brendon Leonard, 8 Dan Baker, 7 Justin Tipuric, 6 James King, 5 Alun Wyn Jones (c), 4 Rory Thornton, 3 Ma’afu Fia, 2 Sam Parry, 1 Nicky Smith
Replacements: 16 Scott Baldwin, 17 Paul James, 18 Rhodri Jones, 19 Lloyd Ashley, 20 Olly Cracknell, 21 Sam Underhill, 22 Tom Habberfield, 23 Kieron Fonotia
Scarlets: 15 Liam Williams, 14 Johnny McNicholl, 13 Hadleigh Parkes, 12 Scott Williams, 11 DTH van der Merwe, 10 Rhys Patchell, 9 Gareth Davies, 8 John Barclay, 7 Will Boyde, 6 Aaron Shingler, 5 Tadhg Beirne, 4 Jake Ball, 3 Samson Lee, 2 Ken Owens (c), 1 Rob Evans
Replacements: 16 Ryan Elias, 17 Wyn Jones, 18 Werner Kruger, 19 Tom Price, 20 Josh Macleod, 21 Jonathan Evans, 22 Dan Jones, 23 Steff Evans
Date: Tuesday, December 27
Venue: Liberty Stadium
Kick-off: 15:00 GMT
Referee: Andrew Brace (Ireland)
Assistant Referees: Dan Jones (Wales), Wayne Davies (Wales)
TMO: Tim Hayes (WRU)