In last April's quarter-finals, the London side went to Spain full of hope after a 2-2 draw at home. They even took the lead only to be shredded by Lionel Messi who scored four times to earn his side a 6-3 aggregate win.
This time, Arsene Wenger's team have gone one better after a smash and grab raid in north London when Messi was strangely profligate by his own stunningly high standards.
Quite what the Argentine magician has up his sleeve this time only he knows, but Arsenal, like their North London rivals Tottenham Hotspur and Ukraine's Shakhtar Donetsk will have genuine belief that they can reach the quarter-finals.
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Tottenham's first Champions League adventure continued last month with a memorable 1-0 victory in the San Siro against seven-times winners AC Milan and they will be favourites to finish off the Italians at White Hart Lane on Wednesday.
Shakhtar also claimed an away victory in the first leg, 3-2 at Roma, when three goals by three different Brazilians put them firmly in charge. The other tie to be decided this week is Schalke against Valencia after the first leg ended 1-1.
Since those late goals by Robin van Persie and Andrei Arshavin stunned Barcelona at the Emirates, the Gunners have suffered a surprise League Cup final defeat by Birmingham City and on Saturday were frustrated by Sunderland in a 0-0 draw.
What Wenger would give for a slice of the defensive resolve that Sunderland displayed when they try to stop a Barcelona side who at their best are the closest thing to an irresistible force in world football.
While backs-to-the-wall defending is not Arsenal's style - they prefer the game's finer arts - Barcelona may find more obdurate opponents this time round, especially as the emphasis is not on Arsenal to chase a goal.
"The challenge will be to find the right balance between having a team who can defend, as well as one that has a good opportunity, every time it has the ball, to go forward," Wenger, who is without van Persie and Theo Walcott, told the club's website.
Barcelona, who rested some of their key players for Saturday's 1-0 win against Real Zaragoza, are without injured captain and central defender Carles Puyol.
Milan maintained their Serie A title charge with a 1-0 victory over Juventus on Saturday when Gennaro Gattuso scored his first goal for three years.
The bearded midfielder will be missing, however, when Milan try to turn around their tie at Tottenham, having been suspended for five European matches after head-butting Tottenham assistant coach Joe Jordan in the San Siro.
Milan also have key players such as Andrea Pirlo absent through injury, although Tottenham will remain wary of a side featuring Zlatan Ibrahimovic and Robinho and possibly Pato in a three-man attack should m
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