Women's Champions League: Chelsea 1-0 Fiorentina
Chelsea outplayed Fiorentina but had to settle for a mere 1-0 lead in their Women's Champions League last-16 tie.
Karen Carney's early penalty was the only goal as the Blues were thwarted by several fine saves from Swedish goalkeeper Stephanie Ohrstrom.
The hosts' skipper slotted in from the spot on eight minutes after Stephanie Breitner handled Erin Cuthbert's cross.
Emma Hayes' side will reach the quarter-finals if they avoid defeat in the return leg in Italy on 31 October.
The dominant display from the Blues saw them bounce back from Sunday's heavy 5-0 loss to local rivals Arsenal, but they will be frustrated not to have enjoyed a far greater margin of victory.
Chelsea's fluid play carved out numerous chances, but Fran Kirby flicked over the bar and was later denied by a low save from Ohrstrom.
The in-form keeper then pulled off superb saves to deny Ramona Bachmann, Carney and Cuthbert after the break.
Scotland striker Lana Clelland came on as a second-half substitute for Fiorentina, but they were unable to truly test Chelsea goalkeeper Hedvig Lindahl.
Out-of-form domestically but thriving in Europe
Last season's Women's Super League champions have endured an unexpectedly slow start to their domestic campaign, with just one win from their first five WSL games.
But their Champions League form has been flawless, having enjoyed an 11-0 aggregate win over Sarajevo of Bosnia & Herzegovina in the round of 32.
An away goal in Florence for Chelsea, who are competing in their fourth consecutive European campaign, would likely be enough to see them reach at least the last eight for a second season in a row.
The Blues are England's last remaining side in the competition this term, following Manchester City's last-32 loss to Atletico Madrid.
Should they reach the final in Budapest on 18 May the Londoners would become the first British women's side to do so since Arsenal won a quadruple of trophies in 2007.
Chelsea boss Emma Hayes:
"One goal will do. You only need one goal to win a football match. To not concede is even bigger than getting a second goal.
"We're creating chances, and that's the main thing. They have got to come out now.
"Let's see what happens when they chase the result and leave us with a bit more space."
Fiorentina goalkeeper Stephanie Ohrstrom told BBC Sport:
"Obviously it would be good to have an away goal but 1-0 is nothing to cry about.
"It's a very open game. We showed we are a good team too. We are able to do it. We just need to believe in ourselves.
"I'm very happy and really satisfied. I just tried to make myself as big as possible."
Chelsea: Lindahl, Blundell, Bright, Ingle, Carney (Engman 90+3), Riley, Kirby, England (Cooper 84), Ericsson, Cuthbert, Bachmann (Ji 79).
Subs not used: Telford, Carter, Andersson, Spence.
Goals: Carney 8 (pen)
Fiorentina: Ohrstrom, Guagni, Jaques, Tortelli, Breitner (Adami 71), Parisi, Mauro (Cleland 45), Vigilucci, Kongouli (Bonetti 54), Philtjens, Agard.
Subs not used: Fedele, Adami, Ripamonti, Caccamo, Fusini.