Lucas Digne’s injury-time free-kick earned Everton a point and denied Watford what would have been a sweet victory over former manager Marco Silva.
Silva was sacked by Watford last season after an approach by Everton earlier in the campaign and the two clubs are still in dispute over the Portuguese boss.
And Watford were on the brink of a deserved three points until France full-back Digne stepped up to send a perfect free-kick beyond Watford goalkeeper Ben Foster with only seconds left.
Everton received the perfect start when another former Watford man, Richarlison, gave them an early lead – although the goal had a large slice of good fortune as Theo Walcott should have been given offside in the build-up.
Watford were a threat all night and they capped a fine start to the second half with a 63rd-minute leveller when Roberto Pereyra’s shot hit the post and rebounded in off Seamus Coleman.
They struck again two minutes later when the outstanding Abdoulaye Doucoure rose above Coleman at the far post to beat Jordan Pickford.
Everton were flat throughout, their display summed up when they were awarded a penalty moments after Doucoure’s goal when Christian Kabasele fouled Yerry Mina, only for Foster to save Gylfi Sigurdsson’s tame penalty.
Watford were holding on in relative comfort during six minutes of injury time until Digne’s crucial last-ditch intervention.