Championship side, Reading, have provided the FA Cup upset of the day as they came from behind to beat Premier League West Brom 3-1.
After a goalless first half, Darren Fletcher looked to have put the Baggies on course for the quarter-finals when he broke the deadlock in the 53th minute.
But Paul McShane grabbed a quick reply as he headed home from an Oliver Norwood free-kick and Michael Hector repeated that feat to put the Royals ahead 18 minutes from time.
Saido Berahino and Fletcher had late chances as West Brom sought an equaliser but Chelsea loanee Lucas Piazon settled it in injury time.
Watford saw off Championship Leeds courtesy of an own goal from Scott Wootton early in the second half.
Wootton miscued a clearance and turned into his own net from a Ben Watson cross after 53 minutes.
Leeds were unable to get back into the game and Etienne Capoue, who earlier had a goal disallowed, spurned a late chance to make Watford's victory more convincing.