Arsenal's defence of their UEFA Women's Champions League crown came to an end in devastating fashion.
Jule Brand broke free from her marker to grab a late winner with three minutes left, which was given after a nervy VAR review.
Despite the Gunners' advantage from the first-leg, they started this game in first gear and seemingly couldn't get out of it, as the French team were 2-0 up at half-time.
However, a much improved display after the restart was rewarded by Alessia Russo's goal to level on aggregate that set up a dramatic finish.
Yet, Lyon managed to overcome their second-half adversity to qualify for the final after the German winger's winner.
Story of the Match
Jonathan Giraldez made two changes from the Lyon team that lost at the Emirates Stadium, with Selma Bacha and Melchie Dumornay coming in for Sofie Sva and Korbin Shrader.
The Gunners remained unchanged from their first-leg victory, and made five changes from their 7-0 thumping of Leicester on Wednesday.
Leah Williamson, Kim Little, Russo, Katie McCabe and Olivia Smith all started, whilst Smilla Holmberg, Laia Codina and Chloe Kelly had to settle for the bench.
Arsenal should have seen their first-leg lead evaporate in 90 seconds, but former Ballon D'or winner Ada Hegerberg missed the ball with her kick from just a few yards out.
Six minutes later, Lyon did have the ball in the back of the net after Lindsey Heaps rose highest to convert from a corner, but the goal was chalked off as both Ingrid Engen and Hegerberg were impeding Daphne van Domselaar in offside positions.
In the 21st minute, OL finally equalised on aggregate; Lotte Wubben-Moy's foul on Dumornay gave the French side a penalty kick, which Wendie Renard took, but saw saved by van Domselaar and cleared from danger.
However, the spot-kick had to be retaken as the Dutch goalkeeper was off her line, and the French defender made no mistake second time round, this time sending the 'keeper the wrong way as the hosts had parity.
Nine minutes from half-time, Lyon doubled their advantage in the game and took the aggregate lead, as Kadidiatou Diani escaped Little at the back post to stab Brand's corner into the net from a narrow angle.
The eight-time Women's Champions League winners were excellent value for their advantage at the break, having dominated midfield and limited Russo and Stina Blackstenius in the visitor's attack to just one shot at goal.
A clever free-kick from Mariona Caldentey after the interval that fed Russo in behind the defence almost saw the ball break to Caitlin Foord with only the goalkeeper to beat, however the Australian's outstretched leg couldn't control it and the chance vanished.
Just shy of the hour mark, the Gunners hit the woodwork twice as they stepped up several gears from their first-half display, Blackstenius first hitting the crossbar, before **Smith**found the left post soon after.
With the visitors needing a goal in the final 20 minutes and aiming to build further on what had already been an improved performance after the break, Holmberg and Victoria Pelova were thrown on as Smith and Caldentey departed.
The latter was in the thick of the action immediately, picking up a yellow card only a minute after being introduced, and having a shot from the edge of the box saved.
With a quarter of an hour left, Arsenal finally levelled proceedings; substitute Holmberg ran down the right flank and delivered a cross to the back post where Russo was running towards, and the striker beat both Heaps and Ashley Lawrence to convert the Swede's delivery.
Lyon, who were now on the backfoot, grabbed a dramatic late winner with only three minutes to play, as an unmarked Brand was picked out by Dumornay in the penalty area, with the German netting into the far corner to break Gunners' hearts.
With a lengthy VAR check to make sure the winger was onside, nine additional minutes were given, however Arsenal couldn't fashion any more chances as their title defence came crashing to an end.
Player of the Match - Jule Brand
Ultimately the match winner, but the German put in a display worthy of more than that.
The 23-year-old did also register an assist, but created two other big chances and had an 86% pass accuracy.
At the other end of the pitch, she put in a big shift to help track back, making three tackles and winning all of them to help her defence out.
Of course, she had the awareness and tactical knowledge to make a darting run infield from the wing to beat her markers that led to her crucial goal.