The experienced Frenchman bested the young Portuguese manager. Arsene Wenger changed his tactics at halftime while Andre Villa-Boas decided not to act. This historic 5-3 match was a tale of two halves.

In the first forty-five, both sets of defenders were holding an incredibly high line, and were thrashed for it. Ashley Cole burned Djourou on one wing, while Gervinho was filling in the holes on the other side. Jose Bosingwa was perched up the field without a thought of ever getting back to defend. It looked early on as if the Blues would boss the match.

At halftime, Wenger must have made a few adjustments in order to close the gaps at the back. The Arsenal back four backed off their high line, and, by doing so, had an easier time dealing with speedsters like Ashley Cole and Daniel Sturridge. Andre Santos looked like a different player after the break. The Brazilian left back is one of those players I love to see in the Premier League. He’s a bit overweight, completely unpredictable, and has a bit of Brazilian flair. Santos has already scored two important goals for the Gunners in limited minutes. He could turn out to be Arsenal’s answer to David Luiz, but without the hair.

Chelsea made two horrifying mistakes in the second half that led to Arsenal goals. First, Bosingwa abandoned his position on the right to push inside. This allowed Alex Song to find Santos, and the Brazilian shot past the helpless Cech. The second mistake was the poor pass by Florent Malouda and subsequent slip by John Terry. The fall could have been an example of karma catching up to Terry. Robin van Persie probably would have beat Terry to the ball, but the Dutchman wouldn’t had such an easy time scoring the winning goal had JT stayed upright.

It is true that Petr Cech did not have his best match on Saturday, but no Chelsea player seemed too concerned about protecting him. Three of the five goals were basically one-on-ones. So there’s no point in blaming Cech.

The Gunners experiencing defensive woes is nothing new, but Chelsea’s ineptitude at the back was surprising. Arsenal were missing three of their four first-choice defenders (Sagna, Vermaelen, Gibbs), and even with those players on the pitch, Arsenal’s back four isn’t that strong. Terry, Cole, and Ivanovic are supposed to be top-quality players. There seems to be a systematic problem.

Arsenal scored four in the second half, while Chelsea managed only one tally. The Gunners closed the holes at the back, while Chelsea persisted with their high line. If it had not been for a no-call on Santos and a beautiful (possibly deflected) Juan Mata strike, the Blues may not have scored at all in the final period.

Andre Villa-Boas needs to install some defensive discipline (as well as just plain discipline). Speaking as an Arsenal supporter, I know what it’s like to watch terrible defending week after week. A team cannot win their domestic league with such shoddy defending. As a caller on BBC’s 606 Football Phone-in memorably said after the match, Jose Mourinho would be rolling in his grave.