However, Dominique Janssen grabbed Wolfsburg an important away goal from the penalty spot with 20 minutes remaining.

The Germans reached the final last year and have history with Emma Hayes' side, having knocked Chelsea out of the competition in three successive seasons from 2015-16 onwards, but the Blues go into the second leg with a narrow advantage.

Wolfsburg looked to get on the front foot from the first kick-off and had the ball in the back of the net, but it went in off the hand of Alexandra Popp, who was shown a yellow card.

Chelsea goalkeeper Ann Katrin-Berger kept the scores level going into the second half, first with a save from Firdolina Rolfo, before the ball fell to Ewa Pajor, whose attempted overhead-kick was cleared off the line by Jonna Andersson.

Wolfsburg started the second half in the same manner as they finished the first, with Pajor heading a Svenja Huth cross goalwards, only for it to rebound off the woodwork.

Chelsea took the lead against the run of play through Kerr, with the Australian rounding the goalkeeper before firing home from a tight angle after being found by the in-form Kirby.

Berger made a flying save to keep her side ahead, with a close-range reaction stop to tip Rolfo's volley over the crossbar.

Harder doubled Chelsea's advantage against the club she left for a record fee in the summer, capitalising on a defensive mistake when trying to play it out from the back.

Wolfsburg pulled one back from the penalty spot following a rash challenge from captain Magda Eriksson on Huth, for what could prove to be a vital away goal.

Janssen stepped up and fired the ball into the top corner, giving Berger no chance to add to her saved penalty tally for the tournament. The German saved three against Atletico Madrid across two legs in the previous round.

Berger suffered an injury in the closing moments and had to receive treatment, but she was able to continue.