Didier Drogba rescued Chelsea with an 82nd minute equaliser after Birmingham briefly threatened to end their unbeaten home record.

Walter Pandiani had fired the visitors in front with a hotly-contested goal in the 65th minute.

But the Ivory Coast striker levelled the scores with a simple finish to keep the Londoners on course for their first title in 50 years.

They are still favourites to lift the Barclays Premiership crown even though Arsenal's victory at Middlesbrough cut Chelsea's lead to 11 points at the top.

Blues coach Jose Mourinho returned to the dugout as Chelsea continued their quest for the title.

Mourinho, banned for two Champions League games by UEFA, will be absent again on Tuesday night when the runaway Premiership leaders play the return leg of their quarter-final tie against Bayern Munich in Germany.

Mourinho was back in his usual guise against City - standing by the touchline in his trademark grey overcoat and directing operations once again.

The Portuguese coach was out in the technical area on numerous occasions as Chelsea found it difficult to get to grips with a tenacious City side that denied their midfield time and space to weave its usual brand of free-flowing magic.

Neither side created an opportunity of note within the opening quarter and Chelsea looked distinctly out of sorts.

Their usual firebrand style had been nullified by a hardworking City side who were more than capable of matching the effort and endeavour of the Londoners.

Mateja Kezman, preferred to the rested Drogba and Eidur Gudjohnsen in attack, looked too lightweight to cope with the physical power of Kenny Cunningham and England defender Matthew Upson.

The wide support of Damien Duff and Joe Cole, so often the spark for the home side, produced nothing until the 32nd minute when the England man grazed the foot of the far post after beating three City defenders on a mazy run into the penalty area from the right flank.

In the 35th minute, an error from former Chelsea defender Mario Melchiot almost allowed the home side to take the lead when he lost possession to Tiago on the edge of the six-yard box. But Frank Lampard could not apply the finishing touch to Tiago's cross.

On the stroke of half-time Cole sent another 20-yard effort into the crowd behind Maik Taylor's goal to sum up a disappointing 45 minutes for the leaders.

Clearly unhappy with Alexei Smertin and Kezman's dire first-half performances, Mourinho replaced them with Gudjohnsen and Drogba at the interval.

Chelsea goalkeeper Petr Cech kept the leaders in the game a minute later when he saved brilliantly at point-blank range to deny Darren Carter from eight yards.

The City player struck the ball perfectly from Damien Johnson's pass but Cech somehow managed to palm it away.

However, the danger had not evaporated and it required a last-ditch tackle from John Terry to prevent Pandiani from tucking home the loose ball.

Chelsea upped the pace as a result and when Gudjohnsen found Duff on the left flank in the 56th minute the Irishman's cross was headed just over the crossbar by Drogba.

A minute later Lampard shot narrowly wide after Cole had got free of Jamie Clapham on the left to deliver a low cross into the penalty area.

Duff's first effort was charged down and Lampard could not, for once, turn the rebound inside the post.

Chelsea were livid with referee Chris Foy in the 64th minute as Birmingham took a shock lead against the run of play.

Foy awarded a free-kick against Cole when the player clearly seemed to have won the ball fairly.

The Chelsea midfielder was was booked for kicking the ball away and Foy moved the free-kick 10 yards forward.

But Jermaine Pennant's lob looked to be going out before Upson headed it back into the penalty area from the touchline for Pandiani to fire the ball into the net via Terry and the crossbar.

Chelsea were powering forward in search of an equaliser as their 22-game unbeaten run at Stamford Bridge was in danger of coming to a shock end.

It arrived in the 82nd minute when Drogba hauled the leaders level after Lampard's pass found him unmarked on the edge of the six-yard box.

The Ivory Coast striker wasted no time in slipping the ball beyond Taylor for the leveller.

It set up a frantic finish but the champions elect had to settle for a point.

Teams:

Chelsea Cech, Johnson (Jarosik 69), Huth, Terry, Gallas, Lampard, Smertin (Gudjohnsen 45), Cole, Duff, Tiago, Kezman (Drogba 45).

Subs Not Used: Ricardo Carvalho, Cudicini.

Booked: Cole, Tiago.

Goals: Drogba 82.

Birmingham Maik Taylor, Clapham, Cunningham, Upson, Melchiot, Pennant (Gray 80), Johnson, Carter (Lazaridis 60), Nafti, Heskey, Pandiani (Morrison 87).

Subs Not Used: Blake, Vaesen.

Booked: Cunningham, Nafti.

Goals: Pandiani 65.

Att: 42,031

Ref: C Foy (Merseyside).