WASPS surrendered a half-time lead as they were narrowly beaten 20-18 by Lyon to suffer an agonising defeat in the European Challenge Cup semi-finals.
Dan Robson and Jimmy Gopperth crossed for tries, the latter scoring 13 points, only for the home side to advance to the final in Marseille thanks to a 15-point haul from Léo Berdeu in scorching conditions at Matmut Stadium de Gerland.
And the defeat denied Wasps a place in a European final for the first time in 15 years as they turn their attentions back to the Gallagher Premiership as they try and secure an unlikely play-off spot.
The two teams matched each other in the opening quarter of the half with Jacob Umaga grounding a dangerous chip kick in his own in-goal area before Wasps forced repeated lineouts close to the Lyon line.
And the game remained scoreless midway through the first period as the game became a scrappy affair with both teams struggling for fluidity in their kicking and passing game.
However, Wasps eventually made the breakthrough on 24 minutes when Robson scurried over from the back of the ruck on the short side from close range after a smart 50/22 kick from Umaga gave the visitors an attacking lineout.
Lyon reduced the deficit on 36 minutes through Berdeu’s penalty only for Gopperth to kick a penalty of his own on 38 minutes to send Wasps into the break with a slender five-point lead.
Wasps almost added a second try at the start of the second half only to knock the ball on virtually on the line before Umaga made a superb recovery tackle to earn his side a lineout and prevent a breakaway score.
However, Lyon grabbed their first try on 48 minutes when Berdeu finished a superb team move that began with a quickly taken lineout before converting his own score to hand the French side the lead.
Lee Blackett’s side restored their advantage on 52 minutes when Gopperth kicked his second penalty despite pressure from the partisan home crowd to edge Wasps into a one-point lead.
And the lead changed hands again on 55 points when replacement Yanis Charcosset finished from close range after several phases close to the Wasps line with Berdeu adding the extras.
The home side missed a chance to extend their lead to two scores when Berdeu hooked a long range penalty attempt wide of the posts before the fly-half then kicked a routine attempt wide.
Lyon eventually extended their lead on 64 minutes when Berdeu slotted a penalty from just to the right of the sticks after another period of pressure on the Wasps line.
Wasps thought they had reduced the deficit when Dan Frost ran in to score unopposed only for the TMO to call play back for a knock on by Francois Hougaard in the build-up.
And the visitors came close again when Zach Kibirige fielded a kick before racing down the wing and kicking ahead only to just be beaten to the loose ball and force a goal line dropout.
The away side eventually found their way through on 75 minutes when Gopperth touched down from a powerful rolling maul before landing the conversion to set up a thrilling conclusion.
However, Wasps were unable to find the score they needed as the club look set for a trophyless season with their Premiership play-off hopes out of their hands.