Odion Ighalo ended his goal drought as he netted in Watford's 2-1 win against Arsenal in the quarter-final of the FA Cup at the Emirates on Sunday.
Adlene Guedioura scored Watford's second goal. Welbeck got Arsenal's goal.
Arsenal had the game's first chance when Giroud put the ball in the back of the net in the 10th minute but was ruled offside.
In the 20th minute Nathan Ake made a timely block after a Kieran Gibbs cut-back.
Pantilimon made a quick save off a Callum Chambers low drive into the box in the 23rd minute.
In the 28 minutes, the game was halted following treatment to Troy Deeney following Gabriel's heavy tackle.
Mohamed Elneny had a good chance in the 30th minute but blasted his shot over the bar. Elneny had another chance again in the 41st minute after a brilliant play from Ozil but blazed his effort over the bar.
Campbell came close for Arsenal on 42nd minute only to see his lob go over the bar.
In the 47th minute Giroud met Ozil's corner but his header dropped on the roof of the net.
Ighalo opened the scoring in the 50th minute after holding off Gabriel before shooting pass Ospina.
Ighalo almost doubled the lead in the 53rd minute but didn't get a clean strike on the ball.
In the 62nd minute ighalo almost made it 2-0 but couldn't connect with Ake's cross.
Adlene Guedioura doubled Watford's lead in the 63rd minute off a bullet of a shoot which flew past Ospina.
In the 67th minute Arsenal made three changes, bringing in Welbeck, Walcott and Iwobi for Campbell, Giroud and Elneny.
Gibbs had a chance in the 81st minute but his straight header was held firmly by Pantilimon.
Chambers came close for Arsenal off a Sanchez cut-back only to see his strike narrowly miss the target.
Welbeck made it 2-1 in the 88th minute, off a back-heel pass from Ozil.
Welbeck had a golden chance to equalize for Arsenal but shot wide in front of an empty net.