The LOU will see Marseille.
Opposed to Wasps in the semi-finals of the Challenge Cup, the Lyon club won by a narrow margin at Gerland this afternoon (20-18).
Winners of all their home matches in the final phase, the Rhodaniens finished the job against the British club after a close game.
Led at the break (3-8), the Lyonnais fell behind in the second half thanks to two tries from Léo Berdeu (47th) then Yanis Charcosset (53rd).
Best director of the Top 14, Berdeu added a penalty to give more scope to the score and consolidate the qualification of LOU, a time threatened by the return of Wasps following the test of Jimmy Gopperth (73rd).
Solid to the end, Pierre Mignoni's men will finally have the last word to qualify for their first European final, on May 27 at the Stade Vélodrome in Marseille.
They will face RC Toulon or Saracens, who face each other this Saturday evening in Mayol (9 p.m.).