Sheffield United, making four changes as they rested players in preparation for the play-off semi-finals, finished well beaten by an enthusiastic Watford side.
Blades boss Neil Warnock admitted: "It is hard to go out there when there is nothing to play for and you have rested a few players.
"The players seemed to play as I felt. Maybe they guessed how I felt because I stayed up late last night which I don't usually do before a match." Watford made eight changes to the side that lost 3-0 at home to Reading in midweek.
"We packed the team with youngsters hoping that their enthusiasm would see us through. It doesn't matter if it is the end of the season - it is a game in the first team," said Watford boss Ray Lewington.
"It wasn't a classic game and we played poorly in the first half but in the end I felt we deserved our win." United had the edge in the first half and should have taken the lead after ten minutes. Carl Asaba ghosted past Marcus Gayle but opted to shoot towards the near post with the goal gaping at the far post and he mis-hit his shot wide.
Watford's signing from non-league Northwood, Scott Fitzgerald, then tested keeper Gary Kelly with a header after Anthony McNamee broke down the left.
When Jamie Hand, who was to pick up the club's Young Player of the Year award, slipped the ball through just before the interval, Fitzgerald's first touch took it too near the keeper and the chance was lost.
United, however, also went close when Stuart McCall hit the bar with a fierce shot from 25 yards out.
Early in the second half Mark Rankine fired just wide but gradually Watford began to make more of an impression.
Fitzgerald was frustrated by a fine save from Kelly and in the 65th minute, after Allan Nielsen mis-hit a drive, skipper Neil Cox turned the ball in following a corner.
Another flag kick saw Gayle's goalbound header blocked but Fitzgerald pounced to plant the ball home after 79 minutes to make the game safe.