Swiss referee Massimo Busacca sent off striker Robin van Persie and awarded Barca a crucial penalty in an exhilarating final 45 minutes of their last-16 second leg at the Nou Camp.
With Arsenal holding a 2-1 lead from the first leg, Lionel Messi produced a brilliant late first-half leveller.
neat finish
Sergio Busquets' own goal restored Arsenal's lead only for Van Persie to be harshly dismissed for time-wasting.
Xavi's neat finish and a Messi spot-kick gave Barca a 3-1 win on the night and 4-3 aggregate success to end Arsenal's European campaign.
