Ross Barkley made his Chelsea debut and Eden Hazard scored a slick opener but that was where the celebrations ended for the Blues at Arsenal.
It's Arsene Wenger's hosts who are through to the Carabao Cup final after Granit Xhaka secured a 2-1 win.
Pedro was denied early on after being judged narrowly offside before a powerful header into the back of the net.
But the Blues didn’t have to wait long, with Pedro piercing the Arsenal defence and putting Hazard though with only David Ospina to beat.
Arsenal levelled comically through a bizarre own goal. Mesut Ozil’s looping corner found Nacho Monreal, whose header collected Andreas Christensen and Antonio Rudiger on it’s way into the net.
Granit Xhaka gave Arsenal the lead after tenacious work from Alexandre Lacazette and a generous deflection into the Swiss midfielder’s path.
Here's how Oliver Harbord of Football.London rated the Chelsea player's performance.
Willy Caballero
Could do nothing about the opening two goals where really he was let down by his defence and both efforts were from close range. Didn't really have many problems with crosses from the match and made a superb stop to deny Alex Iwobi. 6
Cesar Azpilicueta
Maybe was caught a bit cold for Xhaka's goal, but could have been more that Bakayoko let him go. A couple of nice crosses in, but not the most dominating performance that he has had. 5
Andreas Christensen
Did pretty well during the night, however would have been disappointed to let Alexandre Lacazette get the ball in for the second goal. Was given a little run around by the striker, although he couldn't get the goal. 5
Antonio Rudiger
He got a goal and an assist tonight, but unfortunately for the wrong team. Couldn't really do much for either as the ball cannoned off him, however not a great night for the German international. 4
Victor Moses
Started the game brightly and looked to get down the right wing well. However, drastically faded as the match went on and picked up a yellow card for a pretty horrible challenge on Alex Iwobi. 5
Marcos Alonso
Grew into the game as it went on, but even though he saw more of the ball he never really did a great amount with it. A dreadful free-kick summed up his night. 5
Tiemoue Bakayoko
Was probably his strongest game for a while and was good defensively and with the ball. Made some nice passes out to the wings and tried to prevent the Gunners from really getting forward. 7
N'Golo Kante
Again not his most dominant game, which has been the case in the last couple of matches. Looked a little frustrated out there. 5
Willian
As been in really good form recently and started brightly. Real shame to see him hobble off though with a suspecting hamstring problem. 5
Eden Hazard
The only one to really show that sort of spark to get Chelsea back into the game and took his goal really well. However, the burden was too much on his shoulders and he couldn't carry Chelsea through. 7
Pedro
Looked bright at first and had the ball in the back of the net, but was offside when really he should have kept himself in line of the defence. Really faded in the second half and no surprise when he was subbed off. 5
Substitutes
Ross Barkley
Was given a welcome back on his debut with a late challenge from Jack Wilshere, and certainly looked a little rusty at first. Got into the game more as it went on, but looked way off match fitness. 6
Michy Batshuayi
Didn't do enough to affect the game. 5
Davide Zappacosta
Didn't provide much else down the right. 5
