I hate to say I told you so

Well, well, well. What were the odds of that result with 13 mins left? Longer than the 16/1 it was at half time.

Arsenal's first ever win against Barcelona. And they did it without compromising Wenger's inimitable style.

The winning goal came from Andrey Arshavin (who still hasn't been in a losing Arsenal team in the Champions League), from a splendid counter attack. Wilshere played an excellent quick ball to Fabregas who, in turn, released Nasri down the right. He held the ball for just long enough to get support and Arshavin stroked the ball into the far side of the net. The Russian will surely have his old confidence back after that.

Barcelona were the better side in the first half, especially after the game had settled down from the frantic early exchanges, but Arsenal grew in the second half and ended up dominating the last 20 minutes. I believe there were three crucial factors that helped that turnaround.

The first was Barcelona's mentality change after 68 mins. Guardiola brought Seydou Keita (a more defensive midfielder) on for David Villa and pushed Andres Iniesta into the left-sided forward role. This may not have made a great deal of difference tactically, and was probably Guardiola trying to get more energy into a combative and congested central midfield area (see point 2), but what it did do was to hand the initiative to Arsenal. Barcelona gave the impression that they were content to go home with a 1-0 lead and Arsenal seized on this opportunity.

The second factor was physical fatigue. The intensity of Barcelona's pressing puts immense pressure on the opposition but also means that their own players are constantly moving around the pitch. The effort required to keep that intensity up for 90 minutes would be almost superhuman and, although many would argue that technically Barcelona's football is exactly that, their players tired and the tempo noticeably dropped around the time Arsenal scored.

The third and final factor was the effect of the crowd. The main criticism wheeled out about modern stadia is that they can never recreate the atmosphere found at more 'old-fashioned' grounds but last night is a prime example of just how wrong the critics are. Van Persie credited the '12th man' in his post-match interview and there can be no doubt that while Barcelona players' legs became heavy, the Arsenal players fed off of the energy of the crowd and finished the game the stronger side as a result.

This isn't intended as a full post-mortem of a game. Koscielny gave a performance that belied his inexperience at this level. Wilshere gave a performance that was astonishing given his age and inexperience. The same goes for Szczesny in goal but the most impressive thing about the game was the quality of the football throughout. Arsenal may have ridden their luck and Barca may have fluffed a few good chances but surely this is the best result for the tie overall. Barcelona will probably get through to the next round but what a game we should be seeing in three weeks time.