LONDON (REUTERS) - Premier League clubs Arsenal, Aston Villa and West Ham United reached the fifth round of the FA Cup as calm returned to the competition on Sunday, ending a weekend, which reminded spectators that David can beat Goliath.

A day after Chelsea and Manchester City were stunned by Bradford City and Middlesbrough respectively, holders Arsenal beat second tier Brighton and Hove Albion 3-2, West Ham United overcame League One (third tier) Bristol City 1-0 and Aston Villa toppled Championship leaders Bournemouth 2-1.

Goals from Theo Walcott, Mesut Ozil and Tomas Rosicky helped Arsenal conquer an obdurate Brighton side and remain on course to defend the trophy they won last season after going nine years without silverware.

"It was hard work," Arsenal manager Arsene Wenger told the BBC. "A typical cup tie where the other team never gives up. "We had to fight until the end but overall we were always leading and missed a few chances as well.

"I believe that is where we won the game (at the start). The results from yesterday maybe got us on our toes and we got off to a quick pace, and I think that surprised Brighton."

West Ham United had substitute Diafra Sakho to thank for sparing their blushes against League One Bristol City as the Senegal international headed Andy Carroll's cross home in the 81st minute to send the Hammers through to the fifth round.

Aston Villa, hoping the FA Cup would provide welcome respite from their Premier League struggles, also secured their place in the next round thanks to a 2-1 victory over Championship (second tier) leaders Bournemouth.

Carles Gil, who signed from Valencia earlier this month, scored a stunning effort to put Villa in front on 51 minutes before Andreas Weimann added a second. Callum Wilson scored a late consolation for Bournemouth, but Villa stood firm to deny the visitors a replay.