Sunderland continued their cup success this season as a much-changed side saw off a poor Southampton team to reach the FA Cup quarter-finals. Saturday's FA Cup fifth round tie between Sheffield Wednesday and Charlton Athletic has been postponed because of a waterlogged pitch. FA Cup holders Wigan kept up the defence of their crown by knocking Premier League Cardiff out to move into the last eight. Manchester City exacted their revenge on a Chelsea side that has beaten them twice in the Premier League this season with a convincing win that puts them in the quarter-finals of the FA Cup.