Damien Duff’s first-half winner ensured Chelsea maintained their five- point advantage at the Premiership summit. Duff scored after 30 minutes, beating Villa keeper Thomas Sorensen after a fine run by Arjen Robben. Chelsea were not at their fluent best, but fully deserved the win against a Villa side that rarely threatened. Robben had a shot kicked off the line by Mark Delaney in the first half, while William Gallas and Eidur Gudjohnsen missed second half chances. Injury-hit Villa made a bright start, with Juan Pablo Angel unfortunate not to get on the end of a cross from Ulises de la Cruz. And Lee Hendrie then had a shot saved as Villa opened confidently, but Chelsea were soon into their stride and took the lead on the half-hour. It was a trademark Chelsea goal, Robben breaking from inside his own half before feeding Duff. who cut inside Gareth Barry before beating Thomas Sorensen at his near post. Chelsea then started to extert authority, with Robben having a shot kicked off the line by Delaney and John Terry’s header flashing inches wide. Villa were forced into a change on the stroke of half-time, with the limping Delaney being replaced by Nolberto Solano. Chelsea continued in the ascendancy after the break, with Gallas narrowly off target and Gudjohnsen denied by a brave diving save from Sorensen. But Villa were always in contention while Chelsea failed to extend their lead, and Petr Cech needed to be alert to hold on to a 25-yard Solano drive. Robben, as ever, was the catalyst for most of Chelsea’s best moves. And he almost set up a goal for substitute Didier Drogba with a cross that flashed past the face of goal.