The Foxes forward claimed his 10th Premier League strike of the campaign, the fourth season in a row he has reached double figures.
In so doing, Vardy continued his habit of being the player to score the first goal of a new manager's reign at King Power Stadium.
But there was another familiar feeling, this time unwanted, about Vardy's goal at Vicarage Road.
Andre Gray's stoppage time winner for Watford meant that the match was the 16th occasion in which Vardy had scored in the Premier League since 2014/15 but had ended up on the losing side.
No other player has seen his goals count for nothing so many times in that period.
It was an eventful match for Vardy, who also suffered a heavy collision with Watford goalkeeper Ben Foster when going for a cross.
Both recovered after long treatment and Foster saw the lighter side of it on Twitter after the match.