Arsenal 1 Chelsea 2

Arsenal's unbeaten run finally came to an end. The defeat came as a shock to us as we had so much belief in the quality of our team especially after the last week's convincing performance against Manchester City. It was the first time in quite a few years that we, Arsenal fans, had gone into one of big games with such optimism.

Some questioned Wenger's decision to leave Mertesacker on the bench, whose performance has been impressive so far this season and was behind Arsenal's solid start to the season. However, who could have predicted set-pieces would become match-deciders. The boss thought this game was going to be an open game and in fact, Chelsea's starting line-up seemed to have supported his assumption. We also expected Koscielny to get the nod for this one, based on Torres' pace and the French defender's impressive performance against Manchester City. Also, he kept the Spanish striker in his pocket when Spain and France met in the Euro 2012.

According to Arsenal.com site's fans opinion poll, fans' favourite centre-back partnership was Vermaelen-Koscielny with 56% of total votes. Mertesacker has his critics about his pace or lack of it, but he compensates it with his positioning. This match exposed the vulnerability of the Vermaelen-Koscielny pairing. They are both aggressive defenders and tend to push the defensive line high on the pitch, which was not seen this season before this game, when Mertesacker was involved. Although Chelsea didn't score from open play, Vermaelen had to foul in order to stop Torres breaking away, which cost us a free-kick that resulted in Chelsea's second goal. In hindsight, Wenger admitted that he might have made a wrong decision, but it is too hash to blame him for that decision.

The team selection was not a problem. It was consistency. There was only one change to Arsenal's starting XI who outplayed the defending champions in the first half. Vermaelen was fit again to take the left-hand side of the center-back positions, with Mertesacker dropped to the bench. Ramsey retained his starting place on the right flank on the back of his excellent performance last Sunday, although he was soon moved to the central midfield, following Diaby's early withdrawal due to a thigh strain. The Welshman's first-half performance was decent at best, but not as good as last weekend and the second-half was terrible. He was rightly taken off in the 66th minute.

The boss kept his faith in Gervinho despite his futility during the Man City game and it paid off. With a beautiful turn and subsequent powerful finish, he scored an equaliser, which sent Arsenal in ascendancy at the end of the first half. His goal came just as we had thought that Arsenal were looking to regroup their attacking at half time and might need something different, perhaps the introduction of Giroud.

Then in the second half, the Ivorian was not as effective as in the first half. We wondered if Gervinho's abrupt halts to his runs were affected by a knock or team tactics in our match review on the Montpellier game, and we found the answer in this game: he stops when he doesn't know what to do with the ball. In this way, he squandered a couple of glorious quick counter-attacking chances, when a few Arsenal players made a run. When substitutes came on in the 66th minute, we thought it was Gervinho who was going to be taken off, but it turned out to be Podolski.

This game was another big test for us, but the disappointing result did not seem to have done much damage to our title credentials, which nobody questioned this time around. This match was a stern test for Chelsea rather than for us as they had a relatively easier run of games compared to ours, their recent league performances were not so convincing, and they failed tests when they faced strong sides, such as Atletico Madrid and Juventus. Many think that there was little in it between the two London sides. It was a close contention. Although there may have been just a little bit too many players who were not at their best, we could still have snatched a victory had it not been for those defensive mistakes.

It was a blow that Diaby suffered another injury, which is likely to force him on the sidelines for a minimum of three weeks. His early retirement upset Arsenal's shape and balance without doubt. Some argue that we might have dealt with the free-kick that led to Chelsea's first goal better if he had stayed on the pitch. As for his replacement, fortunately, Jack Wilshere is not far away from his return. The Englishman will play an hour or so in the U-21 (reserve) game against West Brom on Monday afternoon. Provided that he will come through this game and the following one against Reading on Monday 8th October unscathed, he could feature in a game against Norwich after the international break. In the meantime, hopefully Coquelin, who missed out on the clash with Chelsea through illness, can fill the void Diaby has left.

The season has still a long way to go. One defeat is just a blip, but two defeats can make a crisis when you are a big club. The most important thing is how we respond after a disappointment like this. Fortunately, a chance to show that (and to brighten up the rest of our week) is coming as early as on Wednesday. We expect a good response from the team on Wednesday's night against Olympiacos.

Player ratings

Mannone: 7
With Chelsea registering only three shots on target, he had little to do and could not do much about Chelsea goals.

Jenkinson: 7
On the day when quite a few players who were under par, he maintained his standards, which have improved significantly this season and continue doing so. He won Arsenal fans' Man of the Match with 26% of their votes on the Arsenal.com site, followed by Kieran Gibbs' 21%. It is reported that Roy Hodgson is considering his inclusion in the England squad for the forthcoming World Cup qualifiers amid a right-back injury crisis. If he can continue producing this kind of performances, he may get a call-up. Against Liverpool, he was a better right-back than an England international, Glen Johnson.

Koscielny: 5
He was guilty for the both goals we conceded.

Vermaelen: 6
His foul on Torres led to Chelsea's winner.

Gibbs: 6
Had a decent game, but his positioning, which has improved considerably this season, was dubious in this game. He often left space behind him for Chelsea to exploit, when he got forward. Some sloppy mistakes.

Cazorla: 6
Not up to his high standards. It was a shock for us to learn that he has an off-day as he had been performing consistently well up till this game.

Arteta: 7
Solid as usual.

Diaby: 6
Had a good run and made a decent attempt, which led to the injury.

Ramsey: 5
Disappointing display after last weekend's stellar performance.

Gervinho: 6
Scored a classy goal, but let us down in the second half.

Podolski: 6
Made a couple of great runs and his header forced a brilliant save from Cech.

Subs

Oxlade-Chamberlain: 6
Replaced injured Diaby in the 17th minute. Set up a goal for Gervinho. Some good play, but not at his best.

Walcott: 5
Came on as one of the 66th-minute double substitutions to replace Podolski and Ramsey. Anonymous.

Giroud: 5
Came on as one of the 66th-minute double substitutions to replace Podolski and Ramsey. Had a golden chance in injury time. He had rounded Cech only to hit the side-netting, when he only needed to put the shot on target.