Eight-time champions Lyon controlled most of the first half but were punished for missed opportunities.

Chelsea's Lauren James and Lyon's Delphine Cascarino both hit the post.

Having been knocked out by Lyon in the semi-finals in 2019, Chelsea arrived in France well aware of the difficult task facing them in their pursuit of a last four spot.

Lyon, who have progressed from 12 of their 13 quarter-finals, imposed their dominance early on, creating several chances for striker Eugenie Le Sommer which she could not convert.

Chelsea then demonstrated their ruthlessness in front of goal as Reiten's curling shot - their first on target - nestled in the far corner, before James rattled the post shortly afterwards.

The game opened up in the second half as Lyon pushed for an equaliser and Cascarino almost provided it when she struck the woodwork but Chelsea still posed a threat on the counter-attack.

Emma Hayes' side have the advantage in the second leg at Stamford Bridge next Thursday but there will be concern for key England centre-back Millie Bright, who went off injured before half-time and will have a scan on Thursday morning.

Moments of quality decide tight encounter

Lauren James has been a standout performer for Chelsea in the Women's Super League this season

It was only the fourth time this season the European champions had failed to find the back of the net and Chelsea will be encouraged by their solid defensive display in the second half.

They limited chances and frustrated Lyon, having picked them off against the run of play in the first half to take a slender lead back to London.

"It will give the team a lot of confidence. We looked nervous in the first 15 minutes. I could see a lack of movement but once we settled, we grew into the game and got more confidence," said Hayes.

"The result and keeping a clean sheet will give the team [confidence]. We have massive respect for Lyon. To win 1-0, I'm satisfied, but we know it's only half-time so there's things to improve on."

England international James showed her quality when she powerfully struck the post and set up Sam Kerr for a glorious chance later on - the Australian was flagged offside when she fired over the bar but replays showed she was onside.

However, it was Cuthbert's endeavour to win the ball back which led to Chelsea's crucial winner and she nutmegged Damaris Egurrola before laying it off perfectly for Reiten.

The game was decided by a few moments of quality, which Lyon often produce in their favour, and Chelsea still have a job on their hands to progress - but this is a huge result in their European history.

"I don't want to underestimate how hard it is to come here in a quarter-final. It's intimidating and I think we managed that really well," added Hayes.

"Pressure situations are moments that reveal your character, your wisdom, knowledge and experience. I felt the team delivered those characteristics under pressure.

"If you build consistency in your habits then every day is a Champions League day. We have become accustomed to the competition and we played with a wise head tonight."

Lyon, who suffered a shocking 5-1 defeat against Arsenal in October, could be boosted by the return of star striker Ada Hegerberg for the second leg as she was an unused substitute in France following her return from a lengthy injury.

Meanwhile Lyon defender Ellie Carpenter, who only returned to action last month following a cruciate ligament injury suffered in last year's Champions League final, is set to face England and Scotland in April after being recalled to the Australia squad.