Goals from Spanish forward Santi Cazorla and Czech midfielder Tomas Rosicky after 31 and 62 minutes respectively sealed a smooth passage for the 10-times winners after an open contest in which the visitors played their part.
Arsenal joined fellow top-tier sides Everton, Southampton, Stoke City, Crystal Palace, who won 2-0 at West Bromwich Albion, and Cardiff City, 2-1 victors at Newcastle United in their first outing under Ole Gunnar Solskjaer, in progressing.
Seven-times winners Aston Villa crashed out after a 2-1 home loss to lower league Sheffield United in their third round tie.
Cup holders Wigan Athletic, who were relegated from the Premier League last term, were held to a 3-3 draw by League One (third tier) MK Dons, while losing finalists and league title favourites Manchester City drew 1-1 at second tier Blackburn Rovers.
