The Gunners survived a first-half onslaught by the tournament favourites, when Lionel Messi's men could have been out of sight, but for some brilliant goalkeeping by Manuel Almunia.

Arsenal trailed to a brace from Zlatan Ibrahimovic but hit back to draw, which gives them a fighting chance when they head to Spain.

However, Arsenal's courageous efforts came at a cost as captain Cesc Fabregas - who would have missed the return against his old club after collecting a booking - suffered what he fears could be a broken leg in the penalty incident which had got the hosts level.

Russian forward Andrey Arshavin expects to be out of action for at least a couple of weeks with a calf problem, while manager Arsene Wenger does not expect veteran William Gallas to play again after the veteran defender broke down on his comeback from eight games out.

It could, though, have been much, much worse for Wenger's youngsters had Barcelona capitalised on their early dominance, when Arsenal were made to look ordinary and struggled to gain control of the ball.

Walcott watched the first half from the bench, before making a major impact on the match - which was watched by England boss Fabio Capello - as his equaliser set up Arsenal's impressive finale.

The 21-year-old forward accepts the Spanish giants are a class act, but sees no reason why Arsenal cannot get the result they need to progress next Tuesday night.

"In a way, as a young player growing up and still learning about the game, it was a fantastic experience just to watch some world-class players," Walcott said.

"It was like someone was holding them with a PS3 controller, controlling them all the time."

"Barcelona did play well for 60 minutes and then sort of died off for the last 30 minutes, but to play at that sort of tempo is very hard to do for the whole game.

"We are a very fit team and we came right back at them.

"It will be a very tough game there, but if we get an early goal and frustrate them then it will be a great game.

"We need to get the ball down and play, to frustrate them, like they did to us for the first 15 minutes especially when they kept the ball and created a lot of chances."

Walcott feels the manner in which Arsenal recovered proves they have grown into genuine contenders.

"To see us go 2-0 down a year or two years ago, we might have let our heads drop, the fans might have got on our backs and there would have been a different results," he said.

"Now we have had a few experiences and a few disappointments - like against Manchester United in the semi-finals last season - that we just want to go that one step further and win something.

"We have showed the character that we can do that."

Arsenal were expecting to find out the extent of Fabregas' injury this afternoon - and Walcott was keeping his fingers crossed the influential skipper's worst fears are not realised.

"Cesc is a fantastic player for us and we always want him to play when he can. Hopefully the injury won't be as bad as it seemed out there," he said.

"But we have players who can come in and do a job - Cesc didn't play in the Porto game and we still won 5-0, so we have great players who can come in for him."

Arsenal resume their Barclays Premier League title race when Wolves come to Emirates Stadium on Saturday.

With leaders Manchester United hosting Chelsea, the Gunners could close the current gap, which stands at four points, with victory over Mick McCarthy's relegation battlers - who have won two of their last four games to pull clear of the drop zone.

Walcott knows there is no further margin for error in the wake of last weekend's draw at Birmingham, where Arsenal conceded a stoppage-time equaliser.

"Every single game is a cup tie especially with the league title race," the England forward said. "We need to clock up some points and add to our goal difference to show we are still in the race."