After Hull ran out 1-0 winners over Middlesbrough earlier in the day, the pressure was put on both Watford and Cardiff to produce the goods.
Hull's win meant that Cardiff's Championship lead was cut to just four points, while the gap was the same between the Tigers and third-placed Watford.
Neither side seemed too enamoured with the idea of opening up and offering anything to their opponents in a close game with few chances.
Cardiff's Kim Bo-Kyung looked lively during the opening exchanges, causing confusion among Watford's defence on more than one occasion.
For Watford, the ever-impressive Czech international Matej Vydra was a nuisance for the away side, while Troy Deeney and Ikechi Anya combined well throughout the game.
Deeney had a header cleared off the line in the first half, while Cardiff nearly hit the home side on the break. Craig Conway broke on the counter attack but, with little support, dragged his shot wide.
The visitors responded positively after the restart and Manuel Almunia did well to save Joel Ekstrand's blushes pushing away Joe Mason's strike after he seized on an error by the defender.
As the game began to open up David Marshall was forced into action at the opposite end making a terrific fingertip save to keep out Deeney's header.
Cardiff were forced to try and utilise Aron Gunnarsson's long throw in the closing stages and it very nearly paid off when Kim's close-range effort was deflected wide of the post.
Malky Mackay's former charges looked as though they might have the last word when Deeney found a way through but he was crowded out before he could get a shot away.
Fernando Forestieri also saw his shot bravely blocked over the top during a frantic final few minutes but in the end both sides were forced to settle for a hard-fought point.