LONDON - Arsenal withstood an onslaught from Barcelona to salvage a 2-2 draw and keep alive hopes of beating the defending champion to a spot in the Champions League semifinals, while Inter Milan has the edge over CSKA Moscow after a 1-0 win on Wednesday.

Arsenal's Theo Walcott celebrates his goal against Barcelona during their Champions League quarter-final first leg soccer match at Emirates stadium in London March 31, 2010. [Agencies]

Barcelona comprehensively outplayed Arsenal for the first hour at Emirates Stadium and led through two goals by Zlatan Ibrahimovic before substitute Theo Walcott got a goal back in the 66th and Cesc Fabregas equalized in the 85th with a penalty.

Barcelona captain Carles Puyol was sent off for his part in the innocuous tangle of legs in the area and will also be suspended.

Barcelona, which beat Arsenal 2-1 to win the 2006 final, is still favorite to advance after scoring two crucial away goals.

The Spanish side enjoyed a remarkable 74 percent possession in the first 20 minutes and 62 percent overall against a team widely recognized as the best passing unit in England.

"It was art, I believe," Arsenal coach Arsene Wenger said. "It was football, but it was art."

While Barcelona can advance with as little as a 0-0 or 1-1 draw in front of its home fans next Tuesday, Inter's advantage is arguably less pronounced despite Diego Milito's 65th-minute goal.

Inter must protect its lead, or score in a single-goal defeat, on CSKA's potentially troublesome artificial turf.

"We don't have any time to train on a synthetic surface," Inter coach Mourinho said. "If we had 15 days we could, but we have a game on Saturday and then have to travel for the match on Tuesday."

Barcelona could have been out of sight of Arsenal early on and would have won by a huge margin but for wayward shooting by Ibrahimovic and stellar goalkeeping by Manuel Almunia.

Barcelona had 11 efforts at goal before Arsenal mustered a first in the 23rd minute, with Almunia saving from world player of the year Lionel Messi, Ibrahimovic and Busquets.

"We came away from our place and played our style of football," Barcelona coach Pep Guardiola said. "We've still done a great thing and have a great chance of qualifying for the next round. We are happy with this result because it is a good result when you play away, but we could have killed the game.

"We have to be more focused or we could go out."

Guardiola said the performance was better than any his team mustered last season, when it added the Champions League title to the Spanish league and cup double.

"Last year, we won all the prizes but we never played away in the Champions League like today," Guardiola said. "Never. Never.

"The first 45 minutes was the best my team has played."

Ibrahimovic could have scored a hat trick before he collected a long pass out of defense and lifted the ball over Almunia to just inside the far post with one touch.

The striker made it 2-0 from another long pass, beating offside and taking a touch before smashing an unstoppable shot past goalkeeper Victor Valdes and into the top corner.

That looked to have clinched victory, especially with Andrey Arshavin and William Gallas substituted because of injury, but Walcott surged into the right of the area and hit a shot under the diving Valdes and in at the far post.