Chelsea's flair players leave Wenger with work to do

Fernando Torres (left) gets the better of Arsenal’s Laurent Koscielny (AP)

London's two most successful sides of recent years will make the customary transition to Champions League games this week in different mood. Each will be expected to win, but in Arsenal's case at home to Olympiakos, a tightening-up at both ends of the pitch will be required to offset the bitter disappointment of Saturday's defeat, whereas Chelsea merely need more of the same against the Danish champions Nordsjælland.

Arsène Wenger, right, was upset his team were "passive on both goals" conceded and Laurent Koscielny, at fault twice, is likely to pay the price by making way for Per Mertesacker on Wednesday. The other important Arsenal fixture this week is an Under-21 game against West Bromwich Albion today in which Jack Wilshere and Emmanuel Frimpong will return. As for the European champions, Roberto di Matteo has been charged with simultaneously improving both results and style in order to keep his job. So far, so good on both counts with a three-point lead at the top of the Premier League and acclamation too for artistic interpretation thanks to an attacking trio of Eden Hazard, Oscar and Juan Mata.