O'Leary: Arsenal's strongest central defence

Former Gunner David O'Leary believes that the Per Mertesacker and Thomas Vermaelen combination has the potential to become one of the best Arsenal have had for years.

Speaking to Yahoo.co.uk O'Leary said, "The main two are Vermaelen and Mertesacker. The others are lads that can fill in, really. Koscielny does ok but I don't feel that he's going to get into the best teams that Arsenal are playing against at the moment.

"Mertesacker is a good reader of the game, but pace wise I sometimes fear for him a little bit. Once Vermaelen comes back from injury they'll form a stronger partnership together. They look like probably the strongest pair they have had at Arsenal for a few years."

O'Leary had a few words to say regarding Arsenal's current defensive situation as well.

"They can play great football, but consistently they have conceded too many goals and shown frailties in defence. When they are one up, they might be dominating the game but you often feel the other team has got a great chance of equalising.

"Bringing Mertesacker in will give them a bit more height which will help when they concede free-kicks and corners. I think other teams know when they play Arsenal that they are vulnerable in that position, and that gives them great heart."

The Irishman believes that Wenger has been unfairly targeted by the media and that he is a special manager.

"Arsene Wenger is a fantastic manager. When I left Arsenal we were a big club but Arsene Wenger has moved them onto another level. They’ve even built a bigger stadium because they outgrew the old stadium. He has been amazing in that way.

Everybody knows they play great football but they haven't won anything in recent years which people keep referring to; they will know they need to put that right. They have started to leak more goals but I am sure they will be working to rectify that as well."

O'Leary holds the record for most number of appearances at Arsenal (722) and believes that it is imperative that Arsenal hold on to club captain Robin van Persie.

"Up front you can see Arsenal’s reliance on Van Persie. He is an amazing player, and if they were to lose him it would be a big blow. You see what he does when he's on the field, and what he does when he comes off the bench.

I hope we're proved wrong, but his injury record of staying fit over the whole season unfortunately hasn't been great.

"The contract issue with Van Persie is potentially a difficult one. Arsenal are a great club and they'll be able to offer him a fantastic deal. But he may be thinking to himself: 'Are Arsenal going to win anything, can I go to a club that has a chance of winning the Champions League and could maybe offer me an even more amazing contract than the one I'll be offered at Arsenal?' I hope that he stays at Arsenal for many seasons to come."