Chelsea are unbeaten after eight matches and lead their London rivals on goal difference, proving that the millions sunk into the London club since their takeover by Russian tycoon Roman Abramovich are paying off.

Steve Bruce's Birmingham side moved up a place into fourth after a match featuring few goal-scoring chances.

Birmingham are building this Premiership campaign on a stubborn defence as Joe Cole discovered in his frustrating first start for Claudio Ranieri's multi-million-pound team.

The best chance of the match came after seven minutes, when Chelsea full-back Wayne Bridge's pass found Jimmy Floyd Hasselbaink but defender Jamie Clapham cleared the Dutch striker's goalbound effort.

Argentina striker Hernan Crespo drew a fine save from Birmingham keeper Maik Taylor with a volley, and Taylor had to be sharp to save Crespo's low shot just before the interval.

Birmingham winger Stan Lazaridis posed a constant threat to Chelsea but the home side's intention were clear as they fielded a lone striker in Christophe Dugarry, with David Dunn tucked just behind him.

The French forward unleashed a 20-yard shot in the first half, but Carlo Cudicini gathered his effort with ease.

Ranieri brought on Eidur Gudjohnsen for the ineffective Cole after the break, but Chelsea failed to find a way through.