Arsenal survived a Barcelona masterclass to stage a stirring recovery and come from two goals down to keep their Champions League hopes alive at the Emirates. Goalkeeper Manuel Almunia produced a string of stunning saves to keep the reigning European champions at bay as they passed the Gunners into submission in a magical first half-hour that had everything except the goal Pep Guardiola's side deserved. The north Londoners, who lost Andrey Arshavin and William Gallas to injury before half-time, looked to be on their way out of Europe and potentially on the wrong end of a humiliating beating as Barcelona finally struck twice in the opening stages of the second half. Zlatan Ibrahimovic took advantage of Almunia's charge from goal to score seconds after the break before then grabbing a crucial second away goal with a rising drive as the Swedish striker collected Xavi's pass on the hour - his first goals in 11 games against English opposition. Nicklas Bendtner saw Arsenal's best chance saved by Barcelona keeper Victor Valdes - but it was the introduction of substitute Theo Walcott that finally gave Arsene Wenger's team the impetus to claw their way back into a tie that looked way beyond them. He raced clear to fire under Valdes with 21 minutes left - and Cesc Fabregas turned logic on its head, given the evidence of the previous 85 minutes, by scoring from the spot after he was brought down by Barcelona captain Carles Puyol. Puyol was sent off and misses next week's second leg, as will Fabregas after he picked up a yellow card in the first half. Fabregas left Wenger with another worry as he limped painfully through the closing minutes after aggravating a leg injury scoring his penalty. Barcelona are in pole position to make their way through to the semi-finals, but they will curse taking their foot off the gas and offering Arsenal some hope when they travel to the Nou Camp for the second leg. Former Arsenal striker Thierry Henry was warmly welcomed when he made a brief appearance as a substitute, but his impact was minimal. Gunners boss Wenger risked Fabregas, who needed a fitness test in the warm-up, and brought back Gallas after an eight-game absence with a calf injury. Barcelona illuminated the opening exchanges with a virtuoso display of passing, pace and movement that left the home side devoid of any meaningful possession - and it was only the much-maligned Almunia and Ibrahimovic's wastefulness in front of goal that kept the teams on terms. Lionel Messi set the tone with a run that sliced Arsenal apart in the opening seconds. It resulted in a corner and a fine save low down from Almunia to halt Sergio Busquets. Almunia stood alone and exposed as a defiant one-man barrier in the face of a barrage of Barcelona attacks as Arsenal were comprehensively ripped to shreds by the quality of the holders' approach play. He blocked Messi and then Ibrahimovic spared Arsenal when he blazed over the top with the goal at his mercy after being set up by Dani Alves' inviting cross. Almunia also saved twice in quick succession to deny Ibrahimovic and Xavi while Alex Song cleared off the line from Alves as the Gunners simply had no answer to the Catalan giants. They finally ended the siege after 23 minutes when Samir Nasri broke into the area and curled a shot narrowly wide with Valdes struggling. The home side's attempts to establish any sort of foothold in the game were hampered by an early injury to Arshavin, who was replaced by Emmanuel Eboue. Gallas failed to last until half-time with a recurrence of his calf injury and another blow arrived just before half-time when Fabregas was harshly booked for tangling with Busquets. After somehow making it through to half-time without going behind, Wenger was left desperately frustrated to see his side concede within seconds of the restart - with the previously impeccable Almunia badly at fault. He made a rash charge from his goal as Ibrahimovic went in chase of Gerard Pique's long ball, leaving the striker with the easy option of lofting the ball over the onrushing Almunia to give the visitors the lead they thoroughly merited. Bendtner should have equalised for Arsenal after 53 minutes when he arrived on the end of Gael Clichy's cross, but his header from eight yards was brilliantly turned away by Valdes. Barcelona responded in style with a second goal just before the hour, Ibrahimovic taking advantage of flat-footed defending by Arsenal to collect Xavi's pass and lash a powerful finish high past Almunia at his near post. Arsenal's spirit in the face of such superiority from their opponents was admirable, and substitute Walcott offered them hope in the 69th minute when he scored low under Valdes, who should have done better. Messi had been relatively subdued after his early brilliance, but he broke the shackles to burst clear and force another excellent save from Almunia as the Spanish giants refused to take a backward step. Goalscorer Ibrahimovic was then replaced by Henry, who was deservedly afforded a wonderful reception from the Arsenal fans who still idolise him. Suddenly, however, the momentum was with Wenger's men and, with five minutes left, they were level after Puyol bundled over Fabregas as he prepared to shoot in the area. Puyol was sent off and the Arsenal skipper completed the formalities from the spot. It was more than the Gunners deserved on the balance of the game, but means they travel to Spain next week still harbouring ambitions of a place in the semi-final. Source: BBC