Chelsea v Arsenal: Key battles

Fernando Torres will have to compete with Demba Ba for a starting spot. Photo: PA

Chelsea welcome Arsenal to Stamford Bridge on Sunday as they look to arrest a worrying slump in home form.

Here, Press Association Sport looks at the battles which could prove decisive in the London derby.

DEMBA BA v THOMAS VERMAELEN

Ba should get the nod over Fernando Torres despite worries about the Senegalese's persistent knee injury. Ba has been in fine form since his move from Newcastle, scoring three goals in three starts whereas Vermaelen has struggled to get the consistency he displayed during his early days at Arsenal.

JOHN TERRY v THEO WALCOTT

At the other end of the pitch Theo Walcott will be hoping to put his pace to good use against Terry in what will be the defender's first start since November. Walcott has shown flashes of brilliance in the role of lone striker this term and Terry will need to be switched on if he is to stop the rapid forward.

FRANK LAMPARD v JACK WILSHERE

Wilshere underlined his importance to Arsenal on Wednesday night when he scored a superb winner in the FA Cup third-round replay against Swansea. Lampard, who has operated in a deeper role under Rafael Benitez, is also at the top of his game, however, and will want to remind the 21-year-old that he remains one of the most potent England midfielders around.