Wolfsburg were left out of missed opportunities as Chelsea took a 55th-minute lead thanks to a clever link play between Fran Kirby and Sam Kerr, with the Australian goal.
Harder then capitalized on a defensive gap to insert the ball into the bottom corner.
However, Dominique Janssen caught Wolfsburg an important goal outside the penalty spot with 20 minutes remaining.
Chelsea: Berger (8), Bright (6), Ingle (6), Andersson (7), Eriksson (7), Charles (7), Leupolz (6), Ji (6), Kirby (7), Kerr (7), More difficult (7).
Submarines: Reiten (6), Cuthbert (6).
Wolfsburg: Kiedrzynek (6), Hendrich (6), Doorsoun (6), Oberdorf (7), Janssen (6), Huth (7), Popp (7), Rauch (6), Rolfo (7), Engen (6), Pajor (7).
Submarines: Jakabfi (6), Blomqvist (6).
Player of the match: Ann-Katrin Berger.
Harder helps Chelsea win in first leg
The Germans reached the final last year and have a history with Emma Hayes’ side, having knocked out Chelsea from the competition in three consecutive seasons starting in 2015-16, but the Blues start the second leg. with a slight advantage.
Wolfsburg looked to gain the front foot from kick-off and had the ball in the net, but it came out of the hand of Alexandra Popp, who received a yellow card.
Chelsea goalkeeper Ann Katrin-Berger kept the same score in the second half, first thanks to a save by Firdolina Rolfo, before the ball fell on Ewa Pajor, whose kick attempt was cleared from the line by Jonna Andersson.
Wolfsburg started the second half the same way they did the first, with Pajor heading a cross-goal from Svenja Huth, only for him to bounce off the woodwork.
Chelsea took the lead against the run of the game thanks to Kerr, with the Australian rounded up the goalkeeper before shooting home from a tight angle after being found by Kirby in good shape.
Pernille Harder started against his former side for Chelsea, while Sophie Ingle replaced Erin Cuthbert in midfield. These are the same three forwards and five backs that defeated Everton in Chelsea’s last WSL meeting.
Berger made an mid-air stop to keep his team ahead, with a short-range reaction stop to tip Rolfo’s volley over the crossbar.
Harder doubled Chelsea’s advantage against the club they left for a record amount this summer, capitalizing on a defensive error trying to play from behind.
Wolfsburg pulled one out from the penalty spot following a reckless challenge from captain Magda Eriksson on Huth, for what could prove to be a vital away goal.
Janssen stepped up and shot the ball into the top corner, giving Berger no chance to add to his saved penalty tally for the tournament. The German saved three against Atletico Madrid over two sets in the previous round.
Berger suffered an injury in the last moments and had to seek treatment, but she was able to continue.
Analysis: “Chelsea digs to get the job done”
Former Liverpool Women’s Manager Vicky Jepson speaking on Sky Sports News:
“Chelsea were very lucky to go scoreless at half-time, but then they were very good at putting their bodies on the line. Wolfsburg were at the forefront at the start of the second half, but this opener from Chelsea against the run of the game turned the momentum back in their favor.
“Their confidence was back, and they looked like a different team and got that second goal. Wolfsburg pulled one out from the penalty spot and Chelsea had to hang on until the finish, but it’s their credit for getting the job done. ”
Chelsea are home for Aston Villa in the Women’s Super League on Sunday at 2:30 p.m. They meet again Wolfsburg in the second leg of the Champions League quarter-finals next Wednesday in Budapest.