AZ’s players were furious, disputing the corner and arguing that a goal kick should have been awarded after Villa midfielder Boubacar Kamara lifted his shot over the bar.
Villa were now in control and it was Watkins who made the decisive contribution, running onto substitute Douglas Luiz’s clever pass to head the ball across AZ Alkmaar’s goalkeeper Mat Ryan and into the corner.
Villa probably need only one more point to secure their path to next year’s knockout stages, and with Watkins in this form anything is possible.
Villa (4-2-3-1): Martinez 6; Konsa 6 (Cash 74), Carlos 7 (Torres 90), Lenglet 5, Digne 6; Kamara 7, Tielemans 7 (Douglas Luiz 74); Bailey 6 (Traore 90), McGinn 6, Diaby 5 (Zaniolo 74); Watkins 6. Substitutes Olsen (g), Marschall (g), Moreno, Chambers, Duran, Dendoncker.
AZ Alkmaar (4-3-3): Ryan 6; Sugawara 7, Bazoer 6, Martins Indi 7, Moller Wolfe 6; Clasie 7 (Dantas 88), De Wit 6 (Mihailovic 69), Mijnans 7 (Odgaard 88); Sadiq 5 (Poku 69), Pavlidis 7, Van Bommel 6 (Van Brederode 69). Substitutes Verhulst (g), Deen (g), Penetra, Dekker, Goudmijn, Kasius, Goes.