(CNN) -- Arsenal fought back from going two goals behind to draw 2-2 at home to holders Barcelona in a classic Champions League quarterfinal that more than lived up to all its expectations.
Barcelona tore into their opponents in the opening 20 minutes, with only goalkeeper Manuel Almunia standing in their way.
On at least three occasions, Spaniard Almunia stopped his compatriots with world class saves, preventing Zlatan Ibrahimovic, Lionel Messi and Pedro from getting on the scoresheet.
That enabled Arsenal to go into half-time on level terms, but that was to end just 30 seconds after the break when a long ball caught out the home defence and with Almunia coming, and failing, to get the ball, Ibrahimovic coolly lobbed the ball home.
And the Swedish striker doubled that advantage 13 minutes later when another long pass caught Arsenal square, allowing the former Inter Milan striker to fire home from an acute angle.
Arsenal manager Arsene Wenger decided to bring on winger Theo Walcott, and the England international went on to change the game with his stunning pace.
Just 10 minutes after going 2-0 behind, Walcott cut inside from the right wing, after being put through by Nicklas Bendtner, before sliding the ball past visiting goalkeeper Victor Valdes to bring Arsenal back into the game.
Then, with the clock showing five minutes left to play, a superb Arsenal move resulted in captain Cesc Fabregas being bundled over by his opposite number Carlos Puyol in the penalty area.
Puyol was sent off for the challenge, which deprived Fabregas of a goal-scoring opportunity, and the Arsenal No.4 dusted himself down to fire home the resulting spot-kick against the club where he started his career and is constantly being linked with regarding a possible return to the Nou Camp.
Fabregas, who was rated only 50-50 to play in the match because of a knee injury, finished the match limping heavily but a yellow card he picked up in the first half means he will miss the return leg regardless of whether he is fit or not.
A thrilling encounter also saw Arsenal lose both William Gallas and Andrey Arshavin through injuries, while Barca defender Gerard Pique also collected a booking which means he joins Puyol and Fabregas in missing the Nou Camp clash.
Meanwhile, former Arsenal hero Thierry Henry, who is the Gunners' record goal scorer after eight sensational years with the club, was given a heroes reception by the home fans for his first return since leaving London for Barcelona in 1997.
Although happy with the draw, Wenger was annoyed with the manner that the two goals were conceded.
He told ITV Sport: "We had a difficult start and Barcelona could have scored two or three goals in the opening 20 minutes when we lost the ball too cheaply.
"But my players kept going and both sides missed chances. We played against a great side tonight but gave away two very cheap goals which is really beyond my understanding."
The winners of the tie will face either Inter Milan or CSKA Moscow in the semifinals and Italian champions Inter hold a slender advantage after winning the first leg 1-0 at the San Siro.
A largely disappointing match was settled in the 65th minute when Wesley Sneijder found Diego Milito, and the Argentine striker found the bottom corner of the net with a shot from the edge of the area.