Maurizio Sarri’s men looked home and dry when they went 2-0 up with just 20 minutes on the clock, only for the visitors to come roaring back and make it 2-2.
Truth be told, Arsenal should have been 4-2 up at half-time, but due to their own profligacy, they were only level.
The second period was all Chelsea and they deservedly got the winner when Eden Hazard set up Marcos Alonso and here are The Statesman’s player ratings from a rollercoaster of fixture in West London:
Plenty of shaky moments for the world’s most expensive goalkeeper in his first real test.
Perhaps should have kept out the Mkhitaryan strike.
Excellent ball for Morata and on the offensive, was quite good.
Defensively, however, struggled to cope with Iwobi in the first-half.
Did his job fairly well, but for both strikes, should have been marshalling the defence better.
Like his central defensive partner, kept Aubameyang quiet.
However, that was down more to the Gabonese forward’s profligacy than anything.
Better than Azpilicueta on the front foot for he picked up an assist and scored the winner, but arguably even more suspect while defending.
Looks comfortable enough in his roving role, but he needs to start putting away the chances that fall his way.
The summer signing is settling in well and was heavily involved in all of Chelsea’s good moves.
Almost lit up the tie with a flash of brilliance, but too fleeting in the end.
Will have to do more if he is to retain his place.
Another game, another goal for the Spanish winger.
Not his best game as he was anonymous for large parts, but did the job on the whole.
Is the man labelled as a flop last season back in form after scoring a sumptuous goal?
Encouraging display, must build on it now.
Hardly got a sniff of the ball and might just have lost his starting spot.
Made the difference in the end, with another superb cameo.
Easily their best outfield player, despite not being 100 per cent fit.
Good debut from the Real Madrid loanee.
Came on rather late, but still had the time to miss a few gilt-edged chances.
The amount of flak he gets is perplexing, for if it wasn’t for him, Arsenal could have been humiliated for the second week in a row.
Looked every bit like a man coming back from a lengthy injury layoff.
Outmuscled Morata on some key occasions, but the the Greek didn’t have a great game overall.
Like the rest of the Arsenal back-four, struggled to play in a high line.
Offensively definitely an asset, but he’s still too naive when his side doesn’t have the ball.
Thankfully got subbed off at halftime, surely won’t start next week now?
The French teenager looks like he’s growing into the role.
Could be their signing of the season.
Justified his manager’s faith with an excellent first-half by scoring and assisting.
Ran out of steam, like the rest of his teammates, after the interval.
Where was the German midfielder hiding?
Missed a sitter, but made amends with his fine finish and an assist for Iwobi’s strike.
Needed more in the second period though.
Missed not one, but two sitters in the first half.
Arsenal were outplayed after the interval.
Lacked composure on the ball. Couldn’t quite affect the tie as his manager would have wanted.
Almost forced a shock winner from Kepa, but apart from that it wasn’t anything of note.
Didn’t get the ball in the areas he would have wanted.