Head coach Lyn Jones says London Welsh have learnt their lessons from a heavy defeat to Harlequins earlier in the season and will be more than a match for the champions in Oxford on Sunday.
The Exiles face a tough task going into the game on the back of a defeat at home to London Wasps last weekend, while Quins beat London Irish 26-15 at Twickenham in the Big Game 5.
Jones' men lost 40-3 at the Stoop at the start of the season, but have since won four Premiership outings and collected four bonus points.
“We’ve taken on board a lot of lessons from our first game against Harlequins. We have progressed and developed as a side and have made great improvements in our discipline and our kicking game,” said Jones.
“We are aware they are a very confident side and are top of the League at the moment, we are disappointed after last week and are keen to make amends.”
Full back Ollie Lindsay-Hague has been rewarded for his part in the Harlequins' A League final win with a first Premiership start of the season at London Welsh on Sunday.
Lindsay-Hague scored twice as Quins beat Saracens Storm to lift the first silverware of the season before Christmas and replaces Mike Brown in the number 15 shirt, having last appeared in the starting top-flight line-up in March 2011.
Fit-again centre pairing Jordan Tuner-Hall and George Lowe come in to give Tom Casson and Matt Hopper a much needed rest, while Sam Smith comes in for Ugo Monye on the left wing.
Second row Charlie Matthews replaces Olly Kohn, with Tom Guest starting at blindside flanker ahead of Maurie Fa’asavalu.
The two teams:
London Welsh: 15. Tom Arscott, 14. Dan Caprice, 13. Seb Jewell, 12. Sonny Parker, 11. Nick Scott, 10. Gordon Ross, 9. Rob Lewis, 1. Frank Montanella, 2. Neil Briggs, 3. Paulica Ion, 4. Jonathon Mills ©, 5. Kirill Kulemin*, 6. Ed Jackson, 7. Michael Hills, 8. Adam Balding.
Replacements: 16. Greg Bateman, 17. Tom Bristow, 18. James Tideswell, 19. Matt Corker, 20. Alfie To’oala, 21. Tyson Keates, 22. Alex Davies, 23. Tom Voyce.
Harlequins: 15. Ollie Lindsay-Hague, 14. Tom Williams, 13. George Lowe, 12. Jordan Turner-Hall, 11. Sam Smith, 10. Nick Evans, 9. Danny Care; , 1. Joe Marler, 2. Joe Gray, 3. James Johnston, 4. Charlie Matthews, 5. George Robson, 6. Tom Guest, 7. Chris Robshaw (C), 8. Nick Easter.
Replacements: 16. Rob Buchanan, 17. Mark Lambert, 18. Will Collier, 19. Sam Twomey, 20. Luke Wallace, 21. Karl Dickson, 22. Ben Botica, 23. Matt Hopper.