Town's reserves coasted to victory at a chilly Vicarage Road on Wednesday night thanks to an impressive second half showing.
Watching Town boss Joe Royle left with a big grin on his face after seeing John McGreal put in a commanding performance at centre back and push himself into the reckoning for a first-team recall. Tommy Miller also came through 80 minutes in a good workout.
After a quiet first 20 minutes, Antonio Murray headed a Dean Bowditch cross straight at Watford keeper Steve Graham before Nabil Abidallah saw a couple of longe range efforts whistle wide.
Lewis Price then thwarted Hornets striker Jason Norville from a couple of yards out before Bowditch's header was tipped over from Flack's cross to leave the first half goaless.
Ipswich immediately upped the tempo in the second half when Murray's shot cannoned off the post. Soon after, McGreal put Town ahead when heading home unmarked from a Nabil Abidallah corner.
Norville then wasted Watford's best chance of the night when firing wide before little Nabil Abidallah head home a deep Liam Craig cross to put the Blues 2-0 up on 77 minutes.
Liam Craig wrapped things up with the goal of the night on 83 minutes. He surged forward before unleashing a 25-yard thunderbolt ito the top corner giving the keeper no chance.
Reserves: Price, Mitchell, Barron, Murray, McGreal (Beveridge 80), Nash, Abidallah, Miller (Knights 80), Bowditch (Leabon 90), Flack, Craig. Unused subs: Croll, Ainsley.