Barcelona's Caroline Graham Hansen scored after just four minutes in LondonChelsea will have to come from behind against Barcelona to reach the Women's Champions League final after losing the first leg at Stamford Bridge.
Caroline Graham Hansen superbly curled in the winner in the first half for Barcelona, before the visitors lost England defender Lucy Bronze to injury.
The England right-back went down off the ball holding her knee in the 66th minute, a day after her national team captain Leah Williamson was ruled out of the World Cup with a serious knee injury.
Bronze's injury was the most significant moment of a second half that Barcelona dictated to see out a win that means Chelsea know they must score at least once when they travel to Spain on Thursday for the second leg.
The semi-final was a repeat of the 2021 final in which Barcelona put four goals past Chelsea after 36 minutes - and they threatened to do the same in London.
Graham Hansen was afforded too much space as she cut in off the right and fired brilliantly past goalkeeper Ann-Katrin Berger within four minutes.
Chelsea responded, creating chances of their own through Guro Reiten and Sam Kerr - but Barcelona substitute Marta Torrejon also struck the post late in the second half.
Emma Hayes' side, who are seeking to win the Treble this season, know they will need a strong performance in Spain to overcome last year's runners-up and keep that dream alive.
More to follow.
Line-ups
Chelsea Women
Formation 4-4-2
30Berger
15Périsset18Mjelde16Eriksson7Carter
22Cuthbert28Cankovic8Leupolz21Charles
20Kerr11Reiten
30Berger15PérissetSubstituted forRytting Kanerydat 84'minutes18Mjelde16Eriksson7Carter22CuthbertSubstituted forIngleat 68'minutes28CankovicSubstituted forJamesat 45'minutesBooked at 71mins8LeupolzSubstituted forFlemingat 84'minutes21Charles20KerrBooked at 37mins11ReitenSubstituted forHarderat 84'minutesSubstitutes
1Musovic5Ingle10James17Fleming19Rytting Kaneryd23Harder27Abdullina32OrmanBarcelona Femenino
Formation 4-3-3
1Paños
15Bronze2Paredes4León Cebrián16Rolfö
14Bonmatí21Walsh12Guijarro Gutiérrez
10Hansen18da Silva Ferreira17Paralluelo
1PañosBooked at 90mins15BronzeSubstituted forTorrejónat 67'minutes2Paredes4León CebriánBooked at 41mins16Rolfö14Bonmatí21WalshBooked at 63minsSubstituted forEngenat 85'minutes12Guijarro Gutiérrez10HansenSubstituted forOshoalaat 84'minutes18da Silva FerreiraSubstituted forCaldentey Oliverat 60'minutes17ParallueloSubstituted forCrnogorcevicat 85'minutesSubstitutes
3Codina5Fernández Velasco6Pina7Crnogorcevic8Torrejón9Caldentey Oliver13Coll Lluch19Vilamala20Oshoala22Rábano23Engen30López SerranoLive Text
Match ends, Chelsea Women 0, Barcelona Femenino 1.
Second Half ends, Chelsea Women 0, Barcelona Femenino 1.
Corner, Barcelona Femenino. Conceded by Maren Mjelde.
Sandra Paños (Barcelona Femenino) is shown the yellow card.
Attempt missed. Marta Torrejón (Barcelona Femenino) header from the centre of the box is high and wide to the left. Assisted by Mapi León with a cross following a corner.
Corner, Barcelona Femenino. Conceded by Ann-Katrin Berger.
Attempt saved. Fridolina Rolfö (Barcelona Femenino) left footed shot from the left side of the box is saved in the top left corner. Assisted by Asisat Oshoala.
Corner, Barcelona Femenino. Conceded by Jess Carter.
Attempt missed. Aitana Bonmatí (Barcelona Femenino) left footed shot from outside the box misses to the left. Assisted by Marta Torrejón.
Offside, Barcelona Femenino. Fridolina Rolfö tries a through ball, but Asisat Oshoala is caught offside.
Foul by Mariona Caldentey (Barcelona Femenino).
Sophie Ingle (Chelsea Women) wins a free kick in the defensive half.
Substitution, Barcelona Femenino. Ana-Maria Crnogorcevic replaces Salma Paralluelo.
Substitution, Barcelona Femenino. Ingrid Engen replaces Keira Walsh.
Substitution, Barcelona Femenino. Asisat Oshoala replaces Caroline Hansen.
Substitution, Chelsea Women. Johanna Rytting Kaneryd replaces Ève Périsset.
Substitution, Chelsea Women. Pernille Harder replaces Guro Reiten.
Substitution, Chelsea Women. Jessie Fleming replaces Melanie Leupolz.
Marta Torrejón (Barcelona Femenino) hits the left post with a header from very close range. Assisted by Mapi León with a cross following a corner.
Corner, Barcelona Femenino. Conceded by Jess Carter.
