Playing with 10 men, Arsenal were unable to pull off the difficult task of keeping up with Barcelona on their home field, in a 3-1 Champions League match that saw the Catalans advance to the quarter-finals on aggregate, 4-3.
Lionel Messi scored two goals, one off of a penalty kick, and Xavi scored another in a great victory for the home side.
Arsenal equalized on an own-goal header by Sergio Busquets in the 52nd minute after a Samir Nasri corner kick.
It was all downhill from there for Arsenal.
In the 55th minute, a horrible error in judgement by referee Massimo Busacca resulted in a second yellow card for Robin van Persie, who kicked a ball wide of the net after an offside call, a typical move by a player who couldn't hear the whistle so he kept playing.
It was a terrible turn of events for Arsene Wenger who had to substitute Manuel Almunia for Wojciech Szczesny after the young starting goalkeeper appeared to have a problem with his fingers.
Also, van Persie was the probable substitute for Wenger as the Dutch forward was not playing at 100 percent due to a knee problem, had been issued a yellow card in the first half, was rather ineffective overall, and was playing with a score that would have advanced the Gunners on aggregate so van Persie attacking skills were not needed.
Busacca didn't care that van Persie pleaded for understanding that he couldn't hear amongst the stadium's high volume. The yellow card was issued, and that was it for van Persie.
With 35 minute remaining at Camp Nou, Wenger had only two substitutions available and was under-manned against a Barcelona side that has a propensity to maintain ball possession.
Barcelona would add a goal in the 69th minute as Andres Iniesta cut through the Arsenal defense and found Xavi who found the back of the net when his shot hit a deflection from Bacary Sagna.
Three minutes later, Messi scored off a penalty kick to ice the game.
Barcelona began the scoring after a mental error by Cesc Fabregas in the closing minutes of the first half, which led to a Lionel Messi goal off an assist by Iniesta.
Fabregas and van Persie, the two Arsenal stars that were battling injuries and questionable for the match, turned out regrettable performances.
Fabregas's ill-advised backheel pass in the first half, and van Persie's retaliation foul in the first half that earned him his first yellow card were the two major factors that cost Arsenal the victory.