Gabriel Agbonlahor's goal in the first-half additional time cancelled out Didier Drogba's early opener.

Despite ruining their 100% home record, Chelsea remained on top of the Premiership table with 16 points while Villa are sixth on 13 points.

Chelsea were ahead as early as the third minute when Arjen Robben curled a free-kick into the area and John Terry rose to head the ball.

The keeper reached the ball before the Chelsea captain but he parried it into the path of Drogba, who slotted into the empty net.

This was the Ivorian's eighth goal of the season in all tournaments.

Unmarked Agbonlahor leveled the score just before the break when he headed home from close range after being set-up by Liam Ridgewell.

In the second half, Chelsea pressed hard to restore the lead but failed to score again, especially with Andriy Shevchenko still struggling to find his form.

In the 70th minute, substitute Shaun Wright-Philips rounded his marker inside the area and fired a powerful shot from a tight angle off the bar.

One minute from time, Villa striker Juan Pablo Angel almost stunned the home crowd as his close-range volley hit the side netting.

Chelsea's last attempt came in stoppage time when Wright-Philips crossed the ball to Salomon Kalou at the far post but the Ivorian shot poorly wide.

Elsewhere, Robin Van Persie scored twice, including a superb first-time finish, to help Arsenal come from behind and earn a 2-1 victory over Charlton Athletic at the Valley.

The victory marked manager Arsene Wenger's 10th anniversary in charge of the Gunners.

Darren Bent put the hosts ahead against the run of play the 21st minute after he connected with Jimmy Hasselbaink's low cross to tap-in easily into the empty net.

Arsenal equalized in the 32nd minute when Alexander Hleb provided a neat cross to Van Persie, who controlled it before drilling a low shot home.

The Dutch international sealed the victory four minutes after the break when he leapt to connect with Emmanuel Eboue's back pass, lashing a superb volley into the top corner of the net.