Manchester City's hopes of a maiden Women's Champions League final look slim after a home loss to holders Lyon in their semi-final first leg.
The French side led on two minutes when City's Carli Lloyd handled in the box and Saki Kumagai converted the penalty.
Kosovare Asllani quickly slotted in the hosts' equaliser but Dzsenifer Marozsan soon put Lyon deservedly back in front.
France striker Eugenie Le Sommer added a third after the break to put Lyon in command for the second leg on 29 April.
Champions League debutants City, bidding to be the first English women's team to reach a European final since 2007, almost pulled one back late on but Abbie McManus' effort was palmed onto the woodwork.
The French league champions, who have featured in five of the past seven Champions League finals - winning three - could have won in Manchester by a bigger margin.
Both sides went into the game having kept 13 clean sheets in their past 16 games, yet the match started at a frantic pace, with three goals in the opening 16 minutes.
Lyon had an effort from France captain Wendie Renard cleared off the line even before Japan's Kumagai calmly tucked in from the spot after World Player of the Year Lloyd's handball.
Toni Duggan's fine through ball allowed Sweden's Asllani to level but the visitors were a constant threat and Marozsan quickly drilled in for 2-1 and substitute Le Sommer added further damage from a tight angle in the second half.
Women's FA Cup finalists City - Britain's first Women's Champions League semi-finalists since Birmingham City in 2013-14 - won the English title and League Cup in 2016 and could still theoretically win five trophies in the space of nine months.
But Lyon will now reach 1 June's final in Cardiff if they avoid conceding three goals or more in the return leg in France next Saturday.
Manchester City Women: Bardsley, Bronze, Stokes, Houghton (c), Asllani, Scott, Duggan (Stanway 83), Lawley (Christiansen 81), McManus, Walsh, Lloyd.
Subs not used: Hourihan, Middag, Beattie, Ross, Parris.
Lyon Feminines: Boudhaddi, Renard (c), Kumagai, Majri, Houara-D'Hommeaux, Morgan (Le Sommer 56), Marozsan, Hegerberg, Buchanan, Abily, M'Bock Bathy.
Subs not used: Gerard, Hamraoui, Thomis, Petit, Henning, Seger.