Steve Tandy has promised his Ospreys team can ruin Liam Williams’ Scarlets farewell on Saturday by securing their place in the Guinness Pro 12 play-offs.
The Ospreys travel to Parc y Scarlets on the final day of the regular season looking to join their neighbours in the knockout stages.
Wales full-back and Lions tourist Williams will make his final appearance at his home ground ahead of his summer move to Saracens.
The Scarlets booked their semi-final place with victory in Connacht last weekend and the Ospreys look odds-on to join them.
Tandy’s men require a single match point to seal a top-four finish. The only way they could miss out is if they lose by eight points or more in Llanelli and Ulster claim a bonus-point win over leaders Leinster.
The Ospreys head coach said: “The Scarlets have been the form team in the PRO12 in the latter part of the season and will feel that they are favourites for this one with a big, vocal crowd behind them.
“We’ve got to front up and with a fair bit of travelling support there as always, we want to give them something to shout about.”
The Ospreys make two changes to the team that recorded an impressive victory over Ulster in the penultimate round. Josh Matavesi replaces Ashley Beck at inside centre while Rhodi Jones starts at tighthead prop.
Full-back Dan Evans, who was named man of the match against Ulster, will become the first player in Ospreys history to make 30 appearances in a single season.
The Scarlets are without the injured Jake Ball so Lewis Rawlins starts at lock while Gareth Davies comes in at scrum-half and Scott Williams replaces Hadleigh Parkes in the midfield.
“We’ll be highly motivated as our opponents will be,” said Scarlets head coach Wayne Pivac.
“Both teams are fighting it out for third and fourth – both regions should be proud of what their teams have achieved to date. What a great climax to the round-robin stage.
“It’s a derby, we’re playing for bragging rights for the season.”
Scarlets: 15 Johnny Mcnicholl, 14 Liam Williams, 13 Jonathan Davies, 12 Scott Williams, 11 Steff Evans, 10 Rhys Patchell, 9 Gareth Davies; 1 Rob Evans, 2 Ken Owens (c), 3 Samson Lee, 4 Lewis Rawlins, 5 Tadhg Beirne, 6 Aaron Shingler, 7 Josh Macleod, 8 Will Boyde.
Replacements: 16 Ryan Elias, 17 Wyn Jones, 18 Werner Kruger, 19 David Bulbring, 20 Tom Price, 21 Jonathan Evans, 22 Hadleigh Parkes, 23 DTH van der Merwe.
Ospreys: 15 Dan Evans, 14 Keelan Giles, 13 Kieron Fonotia, 12 Josh Matavesi, 11 Tom Habberfield, 10 Dan Biggar, 9 Rhys Webb (c); 1 Nicky Smith, 2 Scott Baldwin, 3 Rhodri Jones, 4 Bradley Davies, 5 Tyler Ardron, 6 Sam Underhill, 7 Justin Tipuric, 8 James King.
Replacements: 16 Scott Otten, 17 Paul James, 18 Dan Suter, 19 Lloyd Ashley, 20 Dan Baker, 21 Brendon Leonard, 22 Jonathan Spratt, 23 Dafydd Howells.