Koscielny passed fit for Barcelona tie as Arsenal attempt mission impossible

Arsenal have received a huge boost ahead of their Champions League clash with Barcelona, as defender Laurent Koscielny has been declared fit after recovering from injury.

Koscielny, 30, has been sidelined for nearly three weeks due to a calf problem and hasn't played since the Gunners' disappointing 3-2 defeat against Manchester United.

The Frenchman was involved in full training with the rest of the group over the last four days and should be fit to start on Wednesday as the Gunners' attempt mission impossible.

Arsene Wenger's side have capitulated in the league and FA Cup, only winning once in seven games since their dramatic late win against Leicester in February, and face an uphill battle to overturn Barcelona's 2-0 aggregate advantage.

Speaking to club's official website, Koscielny said that Arsenal can play with more freedom against Barcelona because of their status as huge underdogs.

"We don't have pressure like in the first game, because we play against the best team in the world," Koscielny said.

"People always talk about the statistics and I think we have maybe a five percent chance to qualify.

"But we go to Barcelona with belief and we want to get a result and play a good game."

He could again partner Per Mertesacker in central defence as Arsenal try to cope with Barca's three-pronged attack of Lionel Messi, Neymar and Luis Suarez.

They succeeded in neutralising that trio for 70 minutes at the Emirates before Messi finished off a rapid counter-attack to put the visitors ahead.

"I think we were frustrated with the result because we played well for the first half and then for 15 minutes [in the second]," Koscielny added.

"But physically you feel Barca, when they accelerated the game they were stronger and they scored two goals. After the game we were disappointed with the result."

Arsenal, and especially manager Arsene Wenger, are under increasing pressure following Sunday's FA Cup loss to Watford at home.

Unless they pull off a massive upset on Wednesday, the Gunners will only have the Premier League to focus on for the rest of the season, but they now find themselves 11 points behind leaders Leicester going into another difficult away game at Everton on Saturday.

But Koscielny thinks a good performance against Barcelona would provide a much-needed spark, even if it's not enough to advance.

"If we have a positive result when you play against the best team you have more confidence and it can help us for the rest of the season," he said.

"When you play against the best player in the world or the best team with a good collective side, it can be very important if we can get a result.

"Because we are in a difficult period and we need to stay like a unit and like a team to be stronger.

"We will fight until the end of the season because it's always tight at the top of the table."