Jamal Lowe took his goal tally to six in his last six outings to fire Swansea City back into the automatic promotion places.
Lowe’s goals enabled the home side to recover from falling behind to a 20th minute shot from Tom Cleverley and gave manager Steve Cooper the perfect start to 2021.
Watford arrived at the Liberty Stadium hoping the Christmas bounce given to them by the introduction of a fourth new boss of 2020, Francisco Javier Munoz, would continue against another of their major rivals for promotion.
Lowe scored the winner with a header from a Korey Smith cross in the 67th minute
The Spaniard worked the oracle five days into his job by winning his debut game 1-0 at home against the league leaders, Norwich City, and his magical touch continued a week on when Tom Cleverley hammered home a low shot from the edge of the penalty area to squeeze the ball past the diving Freddie Woodman in the home goal for the opening goal.