Watkins scored a spectacular header just before the hour mark to give Villa the lead, followed by a red card for Fulham's Joachim Andersen. Substitute Issa Diop then scored an own goal just seconds after entering the pitch, all unfolding in a dramatic 10-minute span.
Fulham's afternoon had started perfectly with Raul Jimenez scoring his fourth Premier League goal in five games in just the fifth minute by capitalising on Pau Torres' failure to deal with Bernd Leno's long ball and firing a shot in off the right post.
However, Villa responded just four minutes later when Morgan Rogers' deflected shot from 25 yards wrong-footed Leno and found the net.
Fulham had the chance to regain the lead when VAR adjudged Matty Cash to have handled the ball in the area but Andreas Pereira telegraphed his tame penalty and allowed Emiliano Martinez to hold his effort.
TrendingVilla spurned a golden chance of their own just before the interval as Rogers side-footed with the goal gaping. The visitors, though, started on the front foot again with Leno making two sharp stops to keep out Andersen and then Jacob Ramsey.
But the Fulham goalkeeper could do little about Watkins' superb glancing header at a corner which grazed the underside of the crossbar as it went in and sparked Fulham's 10 minutes of madness.
Watkins tried to burst through on goal and drew a clumsy foul from Andersen, who was shown a straight red card for denying a clear goalscoring opportunity.
Diop hacked Lucas Digne's low cross into the Fulham net with his first touch to compound the hosts' misery although both sides finished with 10 players as Villa substitute Jaden Philogene collected two late yellow cards.
More to follow.