Arsenal Women suffered an immediate setback in their bid to defend their Women's Champions League title as Lyon Women came from behind to record a 2-1 win at Meadow Park in their league-phase opener.
The holders started as they meant to continue in Borehamwood, as with just seven minutes on the board, Alessia Russo propelled the Gunners ahead thanks in no small part to Beth Mead's brilliance.
The latter somehow retained possession amid a sea of Lyon bodies just outside the penalty area, before showcasing nifty footwork to slide a pass through to Russo, who made no mistake with a clinical first-time finish into the far side of the net.
However, disaster soon struck for Arsenal and specifically Daphne van Domselaar, who was culpable for the visitors' leveller just 11 minutes after Russo's fine finish.
The Dutch goalkeeper scuffed an attempted pass out from the back to Steph Catley, presenting the ball on a plate to Melchie Dumornay, whom she thwarted once before the Lyon midfielder converted the rebound.
Rattled by their needless giveaway, Renee Slegers's side were masterminding their own downfall once again in the 23rd minute, when Van Domselaar rolled a seemingly harmless ball out to Ballon d'Or runner-up Mariona Caldentey.
The Spaniard was immediately put under pressure by Lindsey Heaps, whose block/deflection was headed into the path of Dumornay by Katie Reid, and the 22-year-old fired a sizzling second into the top corner from inside the D.
While Arsenal started the second half on the front foot, the French outfit soon wrestled back control of the game and were not short of chances to add to their lead as the clock ticked down.
Only in the six minutes of added time did Slegers's side go for the jugular, but their attempts were in vain as Lyon took down the reigning champions in their own backyard.
The Gunners will aim to respond away to Benfica - who lost 2-1 at Juventus tonight - on October 16, while Lyon host Austrian side St Polten the day before.
Before returning to European action, though, Arsenal welcome Brighton & Hove Albion for Sunday's Women's Super League clash.