Graham Potter’s side took control at a packed San Siro against a Milan team who had to play most of the match with 10 men after Fikayo Tomori was controversially handed an early straight red card.
The decision to send off Blues man Tomori for fouling Mason Mount in the area in the 18th minute turned the match on its head as Milan had matched Chelsea in the opening stages.
Milan coach Stefano Pioli kept a calm demeanour after a painful defeat but later told reporters: “I definitely don’t think the referee has had one of his better evenings.”
Italy midfielder Jorginho slotted home the resulting penalty, and Pierre-Emerick Aubameyang’s cool finish 11 minutes before the break ended Milan’s resistance and put Chelsea one point ahead of Salzburg at the head of the group.
“It changes the game in terms of what Milan want to do, but for us we still needed to make that count. It’s never straight-forward to play against 10-men, especially here,” Potter said.
“It was a big moment, we still felt that we could do enough with 11 v 11 but the referee made a decision and we have to get on with it.”
It’s been a quick turnaround for Chelsea, who were bottom of the group going into the first match with Milan at Stamford Bridge last week and now lead the way after their fourth win on the bounce in all competitions.
Two straight defeats to Chelsea leave Milan third but they still have a fighting chance of making the knockout stages for the first time since the 2013-14 season.
Pioli’s side are ony two points away from the qualification places and a trip to Dinamo Zagreb and the visit of Salzburg will decide their fate in the competition.
“I don’t think there’s any question that I will need to motivate my players,” said Pioli afterwards.
“We’ll have to prepare as best as possible for the match in Zagreb and I’ll do my best to do that.”
– Tomori fury –
An already scrappy, bad-tempered affair exploded when referee Daniel Siebert dismissed Tomori and gave a penalty to Chelsea after the England defender pulled back Mount who had been brilliantly put through by Reece James.
Tomori could barely believe his eyes when he was sent off and both Mount and Olivier Giroud were booked in the shoving that followed amid deafening jeers from the home supporters.
With an angry cacophony vibrating around the San Siro Jorginho opened the scoring three minutes later, further irritating Italy fans after his spot-kick misses cost their national team qualification for the upcoming World Cup.
Giroud nearly levelled against his old club with a header that whistled just past the post in the 27th minute, but Aubameyang soon made sure Chelsea had an iron grip on the match.
Mount was again involved as he played through both Aubameyang and Raheem Sterling, but it was the Gabon striker who got there first and calmly finished at Ciprian Tatarusanu’s near post.
The Blues’ second, Aubameyang’s third in as many matches, completely took the wind out of Milan’s sails but to their credit they did try to force the issue in the second half, pushed on by their magnificent home support.
Sergino Dest could have pulled one back for the hosts on the hour mark but he slashed an awful effort into the stands when Rafael Leao shot down the left flank and sent over an inviting cross with which the American should have done better.
From there Chelsea were content to keep the ball and take the sting out of a match which had long since been decided.
Read more about Chelsea in the Champions League here.