The wrong roll of the dice shows the importance of Arsenal's newest key man

When we suggested last weekend that Arsene Wenger's decision to choose between Koscielny or Mertesacker to partner the returning Vermaelen in central defence was  a dilemma, we were corrected by an Arsenal fan who insisted it was in fact a luxury.

After a frustrating 2-1 defeat to Chelsea which saw both goals come from set pieces, and Koscielny at the heart of them, Wenger will be kicking himself that he was unable to influence the result in a positive way with his team selection, and it certainly would have felt more like a dilemma post-game.

However to blame the manager a la Piers Morgan with his post-game Tweets "Just don't understand why Wenger dropped Mertesacker for this game. He's been our best defender this season," is not our intention.

It was a 50-50 decision, with both the Frenchman and German offering convincing arguments as to why they should partner the returning captain. Mertesacker as we claimed last week had been Arsenal's best player so far this season, more on that later, while Koscielny was equally impressive against Manchester City and struck up a solid partnership with Vermaelen at the end of last season, including a steely clean sheet at home to Chelsea.

So while it was harsh to drop Mertesacker, you can at least understand how Wenger came to the decision, to replace him with one of last season's best players in Koscielny. It wasn't like the manager dropped a huge clanger and chose to play Squillaci.

As manager there is often little you can do to prevent such mistakes on the pitch once your team has been sent out. Koscielny certainly could have done better for Chelsea's first, when Torres pounced on his uncertainty, leaving most observers to come to the conclusion that Mertesacker would never have let that happen.

Which is fine with hindsight, but tactically, Koscielny's fleet-footedness was a plus point against a speedy and mobile Chelsea attack, with that being one of the German's perceived weaknesses.

But the game showed Koscielny still does have weaknesses in his armoury, or at the least is a little rusty at this stage of the season thanks to his early injury and time spent on the bench.

At the same time it has caused to highlight just what a key player Mertesacker has been in Arsenal's defence so far this season. Saturday was the only time the German had not played in the Premier League, and it was the first time Arsenal had conceded more than one goal in a match. Coincidence?

Saturday was disappointing and frustrating for Arsenal fans, but Wenger does not deserve criticism for what happened on the pitch. It was a roll of the dice in playing Koscielny but one which didn't pay off.

Most notably, the game served to underline just what a key player Mertesacker has been this season, and bet on the German being back involved in the starting line-up very soon.  

image: © Ronnie Macdonald