Arsene Wenger: Arsenal are 95% out

Then, the old frailties returned and Lionel Messi's classy late double gave the visitors a 2-0 win that should make the return game in the last 16 tie at the Nou Camp a formality.

[STORY: Lionel Messi strikes twice to leave Arsenal hopes hanging by a thread]

For the past three seasons Arsene Wenger's side have exited at the same stage, having imploded in the opening home leg.

Last year AS Monaco made off with a 3-1 victory and Bayern Munich left London with healthy leads in the two prior seasons.

Each time Arsenal responded with valiant, if ultimately in vain, away performances but, according to Wenger, this time the battle is already 95 percent lost.

"I felt there was room to beat them tonight, that is the biggest regret I have," he told reporters.

"We felt we could win it and lost our cautiousness to defend. Especially as we knew it was vital not to give them a counter-attack which is when they are most dangerous."

“Technically we were very average. We were naive and that’s what was frustrating," added Wenger.

“It makes it very sticky, if not impossible. We have to go there and fight. They were better than us. There’s no shame to say that.

Arsenal's tactics were spot in the opening half with Barcelona failing to land a telling blow.

The hosts also wasted a glorious chance when Alex Oxlade-Chamberlain shot straight at goalkeeper Marc-Andre ter Stegen and Olivier Giroud fluffed a close-range header.

A goalless draw would have given Arsenal a chance of knocking out the European champions next month, but Wenger's side were punished for abandoning their containing gameplan.

"We lost at the moment when we looked more capable to win it," said Wenger, whose side have fallen at the last 16 stage for five years in a row.

"It's a bit disappointing to give them a goal like we did the first one, I feel we are extremely guilty and have no excuse for that goal."

"We had been disciplined defensively and we knew if we had to keep it 0-0 that was what we had to do," he added.

"They are better than us, everybody knows that, but I feel we could have won the game tonight if we had kept the discipline until the end."

Wenger rarely allows his emotions to get the better of him in the wake of a poor result. The Frenchman is known to resist the temptation of a knee-jerk reaction and his analysis tends to be fairly measured. It is a rarity for him to criticise his players in public.

However, Arsenal’s inability to see out a gameplan that he felt was working has frayed his nerves it appears. Barcelona are, as Wenger says, clearly a better side but the Arsenal boss put in place a tactical plan to counter that. His side had executed it fairly well until they conceded.

The visitors had chances but Arsenal had contained them on the break up until the 71st minute. However, a cataclysmic breakdown in their structure left Lionel Messi free in the box.

Further indiscipline seeped into the home side’s play following the concession of the goal, with the penalty both average and naïve, to use Wenger's words. Per Mertesacker made a hash of a pretty straightforward clearance while Mathieu Flamini was worrying flat-footed as he hacked at Messi's ankles.

Arsenal made two errors and were punished. And that appears to be where Wenger’s frustration stems – he could take being beaten by the brilliance of a better team but, ultimately, Arsenal’s undoing was of their own making.