Learn to tackle!
A huge problem for Arsenal on Sunday afternoon was their inability to tackle effectively. Granted, both sides were guilty of making the odd rash challenge. But the visitors lost out because of it.
Indeed, Laurent Koscielny's foul on Eden Hazard set the tone for the rest of the match, as the Belgian's subsequent penalty meant Chelsea could ease off and control the game.
But the Frenchman wasn't the only culprit, as Calum Chambers earned his fifth booking of the season. Some major work is needed on the training ground.
Mourinho has Wenger's number
The man who needs to deliver that sort of change, Arsene Wenger, will probably admit that the 2-0 loss at Stamford Bridge was not his finest hour. His side were second-best, although he didn't make any major tactical errors (debatable?) on this occasion.
Wenger, though, was clearly riled by opposite number Jose Mourinho, as he ended up pushing him on the touchline. Whatever he may say in the aftermath, if the roles were reversed, he would be talking about how badly Mourinho had behaved.
Arsenal need Theo back
Overall, the Gunners were far from terrible against the Blues. Where they were most lacking, however, was the final third.
The return of Theo Walcott will go some way to addressing that. The pacy England forward offers a real tactical alternative with his sheer speed and attacking instinct and Wenger will be able to breathe an overdue sigh of relief when he comes back to fitness.
Galatasaray are no Chelsea
Walcott's presence will certainly help in the big games, as Danny Welbeck is not yet ready to make a difference on the grandest of stages.
The Chelsea game proved as much. Welbeck was unstoppable against Galatasaray - but the Premier League leaders are a different kettle of fish. The 23-year-old's record against top-four opposition and bigger sides has generally been poor throughout his career. It will take Welbeck time to change that at Arsenal.
Take the positives...
When it comes down to it, though, the north London side came through a tough test with plenty of positives. Let's not forget that this was the Gunners' first league defeat of the season.
The 2-0 margin was also a three-time improvement on last term's 6-0 thrashing, while Arsenal's starting XI looked strong in every area except the final third against a monstrous Chelsea defence.
Wenger's men, moreover, were only beaten by a penalty and a superb Cesc Fabregas - Diego Costa link up. So, though this defeat may hurt, it certainly won't be the be all and end all of Arsenal's campaign.