Manager Arsene Wenger had made several changes from the side which thumped West Ham 5-1 in the Barclays Premier League on Wednesday night, but eventually the Gunners had enough to see off the npower Championship side, who had twice levelled.
In-form Olivier Giroud fired the visitors ahead on 16 minutes before Ashley Barnes equalised with a powerful header.
Giroud netted again on 56 minutes with another well-taken strike, but the Seagulls were level again through a diving header from Argentinian forward Leonardo Ulloa on his debut after joining from Almeria.
Arsenal finally made sure of a place in the last 16, though, when Walcott's shot was deflected in following a corner with five minutes left.
- Sports & Recreation
- Barclays Premier League
- Olivier Giroud