I was at the first leg and would hope Arsenal can continue where they left off. They need to do what they did in the second half at the Emirates and hold a high defensive line which left little space between defence and midfield for Barcelona to exploit. In the first half Barça had been given plenty of room to play and were passing through Arsenal. After the break, though, with Arsenal playing much higher, they were forced to pass in front of Arsène Wenger's team, rarely got behind the home defence and were never able to use their possession to really hurt them. Arsenal made things too tight for a Barcelona side that, at times, even started losing the ball. Some people might advocate fielding a five-man midfield in Spain but I'd go for four and a half in that department with the half fully able to exploit any attacking opportunities that present themselves.
I suspect Wenger will play a five-man midfield and I think it offers Arsenal their best chance of success. They will miss Alex Song and need Abou Diaby to be at his best, if selected, as he will surely be the main defensive midfielder and must help his full-backs out. Arsenal will need to spent a lot of the night containing while playing on the break and hoping to catch Barcelona out with counter-attacks. Their natural game is very much about hitting teams on the break so this is something they are very good at. The containment bit of the night will be largely about limiting the supply to Lionel Messi and trying to force him on to his right foot. He's the world's best player so at times he will damage Arsenal's game but that doesn't mean they should give up doubling up on him. Wenger's players know Messi will look to attack Gaël Clichy's right foot and they need to prevent this happening too often. Even if you manage to keep Messi quiet there are bound to be problems with those around him - Andrés Iniesta, for instance – but an extra man in midfield will help an Arsenal side who will have been hardened mentally by beating Barcelona at the Emirates.
If I were Wenger I would ask Arsenal to defend really deep, while letting Barcelona have the ball and pass it around in front of them before attacking them on the break. I think it's just too difficult to hold a high line and press a team as talented as Barcelona for an entire evening at Camp Nou. Admittedly, if Arsenal lacked pace, you would probably have no option but to go for a pressing game and a higher line but, because Wenger's team are collectively quicker than Barça, they can combine sitting deep with blistering counter-attacks. Arsenal's extreme pace on the break will scare Barcelona and that fear might make them a little less dangerous as an attacking force. I would have Wenger's defence sitting on the edge of the area, leaving little space behind them for Barcelona to exploit with the quality of their passing and movement. If that gap behind Arsenal's backline is too big the risk of defeat increases. I also believe a deep-lying defence will be much better equipped to comfortably combat Barça's crossing.
If Arsenal progress in this tie it would arguably be one of the most notable achievements by an English club in European competition in recent times. Barcelona are world-class throughout their line-up and, even without Carles Puyol and Gerard Piqué, they're only in the same position they were in last season when the sides met and the Spanish club progressed so comfortably. They'll just bring in more world-class players to replace both centre-halves, so Arsenal's task is immense.
If they are to make it through to the quarter-finals, they should not play for a goalless draw. The simple fact of the matter is that they are unlikely to keep Barça out for the entire match – they've scored 78 goals in La Liga alone this season – so Arsenal need to try and play their natural game, most likely within the formation they are familiar with, and put the home side on the back foot by registering an away goal. They can look to hit on the counter-attack, with the trickery of Samir Nasri and Cesc Fábregas, and discomfort the home side that way. That approach does at least allow them to stick to what they are best at.
This Arsenal team are incapable of doing what Internazionale did against Barcelona last season, shutting up shop and piling men behind the ball with very little ambition ever to go forward. That would be against Wenger's philosophy. Sure, they have a good work ethic – like Barça's, in fact – with both sides eager to chase down the ball when it's lost. But, to make the home side work, they have to keep the ball as long as they can when they can steal it from Barça, and make use of it, particularly in wide areas. They will have to be ruthless in front of goal and take what chances that come their way. They scored at Camp Nou last season and created other chances; they need to take them all this time around.
Defensively, Arsenal need to be rock solid through the middle, where so many of Barcelona's clever give-and-goes are generated. The Spanish team attack with pace through the middle, so that's where Arsenal need to be most wary. Song is their most natural defensively-minded midfielder, breaking up a lot of the opponents' play, so to be denied him is a real loss. Diaby is more rangy in his style of play, but it will be a test of his ability whether he has the pace and ability to cope with the quick feet and passing of Iniesta, Xavi and Mascherano.
But the bottom line is that Wenger will want his side to go there and put in a performance, playing the brand of exciting football with which they have graced the Premier League. They need Barcelona perhaps to have an off day – maybe a repeat of the profligacy that damaged them in the first leg – and to take their own chances, while remaining solid down the spine of their side. It's a big ask. A massive ask. But it will be a cracking game.
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