The Ivory Coast hitman gave Chelsea hope when he cancelled out David Silva's impressive first-half goal for Valencia with a 53rd minute header.

The Spaniards made Jose Mourinho's side work hard for their share of the spoils during a thrilling encounter at Stamford Bridge and the draw will give Valencia the edge in the quarter-final return leg next Tuesday.

The English champions opened brightly enough but left-back Ashley Cole rushed a cross which eluded both Didier Drogba and Salomon Kalou as it flashed across the six-yard box.

In the ninth minute, Kalou hit the crossbar from the edge of the penalty area after Roberto Ayala had blocked Andriy Shevchenko's path to goal with a crude challenge.

Ayala's block went unpunished by Belgian referee Frank De Bleeckere despite Chelsea's appeals for a penalty.

Two minutes later Villa squandered a chance when he failed to hit the target from close range after escaping the shackles of the Chelsea defence.

Valencia missed another good chance to take the lead in the 21st minute when Joaquin's shot found David Silva unmarked in the penalty area.

Silva only had to touch the ball goalwards to beat Cech but mistimed his kick completely and the Blues escaped again.

Seconds later former Chelsea left-back Asier del Horno tested Cech with a 25-yard volley which the Czech international dived to his right to clutch.

Valencia's pressure paid off in the 30th minute when Silva sent a 25-yard angled drive flashing past Cech and into the far corner of the net. It was just reward for the Spanish side.

Two minutes before the interval David Albelda was booked for a foul on Cole - and from the resulting free-kick Michael Ballack headed wide from six yards.

Chelsea started the second half in a much more positive fashion and Kalou was unlucky when he mistimed a shot from a cross by Lassana Diarra.

There was far more urgency about Chelsea's play now and for the first time in the game they looked capable of unsettling their opponents.

Lampard wasted a free-kick after Drogba had been brought down by Ayala - hitting the ball straight at Valencia's defensive wall.

But Chelsea's higher tempo football paid off in the 53rd minute when Drogba equalised.

It was more of a case of route one football for the champions as Cole's long clearance bounced fortuitously inside the penalty area for Drogba to head over the advancing Canizares.

Chelsea's equaliser had given them even more impetus and the Spanish side were having to defend at length for the first time in the contest.

The Blues were now winning the majority of the challenges in the midfield and collecting the all-important knock-downs as they continued to pile on the pressure.

A second goal give them more hope in the return leg but when Diarra clever worked an opening for Lampard via the intervention of Drogba, the England midfielder could not direct his shot on target.

Chelsea were now moving the ball with ease across the midfield but they could not deliver the telling final ball when it mattered.

Diarra was guilty of wasting a chance to put more pressure on the Spanish side in the 66th minute when he tried to chip Canizares from fully 40 yards.

The hosts appealed for a penalty when Shevchenko went to ground under a challenge from del Horno - but all they got for their efforts was a corner.

Mourinho sent on Shaun Wright-Phillips and Joe Cole with 15 minutes remaining in a bid to snatch a winner, for Cole it was his first action since November - and he got a rapturous reception from the Blues fans.

The all-out attack almost paid off seven minutes from time when Canizares flapped at a Lampard corner but Shevchenko's goalbound scissor-kick was cleared off the line.