Former Watford boss Graham Taylor returned to the club where he made his name to have a stand renamed in his honour, but then had to look on as Adam Le Fondre netted the only goal to condemn the Hornets to their fourth straight defeat in the Sky Bet Championship.
A host of great Watford names, who were either on the coaching staff or played under Taylor during his two hugely successful spells with the club, formed a guard of honour prior to kick-off as the Rous Stand was officially renamed The Graham Taylor Stand.
Cardiff came into the game as one of only two teams in the Championship without an away win, but they made the breakthrough in the 12th minute.
Some sloppy play saw the home side lose possession and when Anthony Pilkington hung up a cross from the right, Heurelho Gomes was beaten to his attempted punch by Kenwyne Jones and the ball rebounded off the post to give Le Fondre the simplest of tap-ins.
Watford had previously started brightly though, with Troy Deeney seeing a goal-bound effort cleared from inside the six-yard box after David Marshall had been unable to hold a stinging Daniel Tozser strike, before the Bluebirds keeper was smartly off his line to thwart Matej Vydra.
And it was the Czech Republic striker who continued to look the most likely source of an equaliser for his side as the first half continued. The Hornets’ top-scorer was unfortunate to get the ball trapped beneath his feet when he only had Marshall to beat, and then a fine challenge from Matthew Connolly prevented him having a clear strike on goal after being released by Deeney.
However, Cardiff might have doubled their lead in the last action of the first half when a Juan Carlos Paredes mistake allowed Le Fondre a shot, but Gomes was equal to it.
However, the story from the start of the second half increasingly became one of the Cardiff goal living a charmed life for the first 15 minutes.
The excellent Marshall denied Gianni Munari from close range within 50 seconds of the restart before the Scotland goalkeeper produced a superb reaction stop to keep out an Almen Abdi’s close-range header. Next, Munari thought he had touched in Vydra’s drilled cross, only to see the ball rebound off the far post.
But the attacking momentum then went out of Watford’s game and Cardiff had a chance to make the game safe in the 80th minute when Le Fondre was able to get to the by-line and cut the ball back to Tom Adeyemi, but his effort was dealt with by Adlene Guedioura.