espnstar.com looks at three key battles that could help decide this weekend's London derby as Arsenal entertain Chelsea.

Thomas Vermaelen vs Nicolas Anelka
Vermaelen has been one of Arsenal's stand-out players of the season - providing a mixture of steel and composure to the Gunners defence.

Perhaps the biggest compliment that can be paid to the Belgium international is that the team has hardly missed the departed Kolo Toure as many expected them to.

Vermaelen is quick, strong in the tackle and plays with a calm assurance that belies his young age. He also has something of a goal-scoring touch about him - as his five goals already this season will attest.

Comfortable in the air and on the ground his all-round game provides the Gunners with the stability they need in order to make the most of their attacking talents.

Anelka is playing the best football of his life in a Chelsea team that seems to exude confidence at the moment.

The Frenchman is blessed with extraordinary pace and will be a threat all day as the Chelsea midfield look to play him in behind the Arsenal back four.

In addition to pace Anelka has struck up a fantastic partnership with Didier Drogba so look out for their link-play if the big Ivorian returns from injury.

A more mature player now than when he turned out for the Gunners in the early part of his career Anelka is a great finisher so expect him to make the most of any chances that come his way.

Theo Walcott vs Ashley Cole
Walcott has only recently returned to the Arsenal team after being out injured - but will pose a very real danger to the league leaders with his pace and trickery.

He is lightning quick and will try to put his opposite number on the back-foot with his direct running and dribbling skills.

With a nice first touch and an eye for goals look out for him moving infield as he attempts to link up with his forwards or shoot for goal.

On his day he can be unplayable.

Cole is another Chelsea player in the form of his life - seemingly benefitting from playing under Italian coach Carlo Ancelotti.

England's first choice left-back is quick, tenacious and has the energy to both defend and attack for the full ninety minutes.

Not only can he stick to his opposite number like glue but he has the ability to play his way out of trouble and offers a pinpoint delivery from the Chelsea left flank.

Andrei Arshavin vs Michael Essien
Arshavin is an attacking midfielder who is blessed with great ball-control, excellent vision and the ability to drift past players with a surprising turn of pace.

His quick feet and even quicker thinking can leave opponents grasping at thin-air as he makes space for himself with a shimmy or clever one-two.

He is both provider and finisher - so look out for him getting into advanced positions where he can play a killer ball or demonstrate his own cool finishing.

Essien is some people's idea of the perfect midfielder - a blend of skill, pace, power and poise.

The Ghana international is an all-action player who can defend as well as attack and is a domineering presence in the middle of the park.

Currently employed as the holding midfielder in the Chelsea diamond he is adept at breaking up play and then releasing his attacking colleagues.

With boundless energy he is as effective in the last minute as in the first.