A goal in each half from Joe Mason earned City a third consecutive pre season victory.
Mason opened the scoring as City took a 1-0 lead over newly promoted Watford in the 19th minute.
A strong run from Scott Malone ended with a shot that was parried by Heurelho Gomes to Joe Ralls, Ralls played the ball back into the box where Mason was sharpest to react and turned the ball past the helpless Brazillian.
Moments later Peter Whittingham fired just over. City were lively with Amoebi causing problems and Mason buzzing around the edge of the box. Malone was keen to push forward at any opportunity.
The equaliser came against the run of play when a ball over the top was collected and finished by Troy Deeney. City were unlucky to be level after a promising first half.
Watford came out after the break playing more progressive football and some slick passing helped create danger in the City box. The most clear cut chance from the home side came when Kagisho Dikgacoi fired wide.
Despite a number of changes City wrestled the impetus back off the visitors and as a result carved out a winning goal. Pressure on the Watford substitute keeper and a tenacious challenge from Stuart O'Keefe allowed Joe Ralls to against set up Joe Mason for a supebly taken winning goal.
City managed to keep the ball out during a goalmouth scarmble and defended and last minute corner to win the game.
Notable mentions for Scott Malone. Looked very sharp and willing to get forward. To Joe Mason for two well taken goals and I think Sammy Ameobi could be a handful for periods during a game.
FT Cardiff 2 - 1 Watford.
Pic from @jonrcandy