This week’s chalkboard analysis is up at FourFourTwo here, but here are a couple of bonus chalkboards on the halftime changes in the North London derby.

The introduction of Sandro at halftime was supposed to provide an additional man in midfield to counter Arsenal’s dominance in this area. It meant shifting Parker from his role in front of the back four, meaning he was generally further up the field in the second half, most notable in his shots and his second booking which was a needless foul late on in Arsenal’s half.

Parker’s more advanced position wouldn’t necessarily have been a problem in itself, had Sandro actually fulfilled his duties. Instead of adopting a central position, he could quite often be found on the right side, most notably for Arsenal’s third goal when he was on the right wing as Rosicky burst through the middle to score.

The movement of Bale to the right in the second half also made little sense (as noted in the FourFourTwo column). It left Assou-Ekotto exposed behind van der Vaart, when you’d expect Bale in his usual position on the left would have protected his fullback more. Also, the attempt by Harry Redknapp to use out-to-in wingers put the onus on Assou-Ekotto to push forward in attack to provide width, meaning he was often found further up the field in the second half and Arsenal ruthlessly exposed the space created in behind him for all three of their second half goals.