This was a big moment in time for Graham Potter.
The night when Potter proved he is up to the job, ready for the challenge of being Chelsea manager and revelled in a big European occasion.
It was by far and away Chelsea’s best performance of Potter’s three-game reign as their slick football, movement and style blew even the might of Milan away.
Stamford Bridge was back to its best, a raucous night when Thiago Silva rolled back the years, Wesley Fofana scored his first goal for Chelsea, Pierre-Emerick Aubameyang got himself among the goals again and local hero Reece James put in another superb display.
If there was any doubt about Potter’s credentials - the manager who admitted Grahams are not usually known for being sexy - then he even looked the part on the touchline with his stylish black roll neck jumper making him look like the Milk Tray man.
But it was also about the energy in the stadium because the fans will take to him if Chelsea carry on delivering performances like this.
Twenty-four hours on from Trent Alexander-Arnold scoring a sensational free-kick at Anfield, James showed that he can defend, attack and score in an all-round display which perhaps goes to show maybe Gareth Southgate knows what he is doing after all.
To be fair to Milan, the Italian giants were missing big players, they were far from their best and Fikayo Tomori had a night to forget as he and Olivier Giroud had miserable returns to Stamford Bridge.
But it was also about Chelsea because they set the tone, they set the pace and, from the very first whistle, looked ready and determined.
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Silva, even at 38, just looks a Rolls Royce of a defender who plays the game at his own pace, reading danger and stepping up when needed to launch attacks.
The Brazil veteran saw an early header well saved by Ciprian Tatarusanu who also denied Mason Mount but Milan’s No.2 keeper did look vulnerable all night and Chelsea took full advantage with a 23rd-minute opener.
Ben Chilwell’s corner was flicked on by Silva - who else - and there was an almighty scramble in the Milan box before Fofana forced home from close range. It was a big moment for the £80 defender even if he limped off injured soon after.
Chelsea were so on top and yet survived an almighty let-off in first-half injury time. Chelsea keeper Kepa Arrizabalaga denied Charles De Ketelaere, the loose ball was deflected to Rade Krunic who seemed certain to score only for his shot to be deflected over by Chilwell.
While it was 1-0, Milan were still in it. But that all changed after 56 minutes. James cut in from the right, he put over a cross and Tomori failed to cut the ball out. It was a horrible moment for Tomori.
It presented Aubameyang with an easy chance to score his second goal in as many games and the former Arsenal striker is rediscovering his goalscoring touch.
Chelsea then killed off the game after 62 minutes. Raheem Sterling charged forward, laid off a perfect pass and there was James to smash home into the top corner to round off an impressive win.
After a stuttering start to their Champions League campaign, they could not afford any more slip-ups and, on this evidence, Chelsea will not fear next Tuesday’s return game in the San Siro.