Almen Abdi took just nine minutes to mark his return to first team action with a goal, Ikechi Anya adding a second before the break to send Watford in 2-0 up at half-time.
Beppe Sannino made four changes to the team which drew against Burnley on Saturday, handing Albert Riera his full debut in place of Daniel Pudil, whilst on the other side, Anya moved forward to partner Troy Deeney, with Davide Faraoni taking Mathias Ranegie’s place.
Reigning Player of the Year Abdi made his first start since August 31 in place of the injured Cristian Battocchio, whilst Sean Murray was preferred to Lewis McGugan.
Abdi was bright from the outset, gliding into the Leeds penalty area in the opening minutes and sitting up a cross for the unmarked Faraoni at the back post, the wing-back seeing his shot blocked.
The Swiss marked his return to action in style in the ninth minute, stooping to meet Anya’s cross from the left to give Watford the perfect start.
Leeds caused Watford very few problems despite seeing plenty of the ball; Ross McCormack’s audacious effort from just inside Watford’s half as good as it got for Brian McDermott’s side.
Watford doubled their lead in the 32nd minute, Riera’s cutback falling to Murray who helped the ball out to Faraoni on the right, the Italian crossing for Anya to nod home at the far post.
Comfortable on the ball, Watford were never stretched by Leeds, who were unable to put their possession to use in a penetrative fashion.
Watford: Almunia; Angella, Cassetti, Ekstrand; Faraoni, Murray, Tozser, Abdi, Riera; Anya, Deeney.
Subs: Bond, Belkalem, Merkel, McGugan, Ranegie, Pudil, Hoban.
Leeds United: Butland, Wootton, Lees, Pearce, Warnock, Brown, Tonge, Mowatt, Poleon, McCormack, Hunt.
Subs: Cairns, Smith, Zaliukas, Pugh, White, Murphy, Stewart.
Referee: Mr G Ward