Goals from Antoine Semenyo and Dominic Solanke either side of a superb Leon Bailey strike looked to have secured a third successive Premier League win for the Cherries, but Watkins headed home late on from Moussa Diaby's cross.
How the match unfolded
Bournemouth's only change to the team that won at Sheffield United the previous week was a return to the starting XI for Milos Kerkez, who replaced the injured Lloyd Kelly at half-time in that 3-1 victory at Bramall Lane.
It was a different story for Villa, however, with Watkins declared fit to lead Unai Emery's attack, one of seven changes to the side that beat Legia Warsaw in the UEFA Conference League on Thursday night.
But it was Bournemouth, winners in four of their previous six meetings with Villa, who went ahead on 10 minutes. It was a moment to forget for Villa's Diego Carlos as he passed the ball straight to Ryan Christie, who in turn found Semenyo free in the area to score.
Semenyo drew a fine 16th-minute stop from Emiliano Martinez at full stretch, and that save proved crucial as Villa were back on level terms four minutes later when Watkins picked out Bailey in space on the right, and he cut in before sending a superb effort beyond Neto.
Villa thought they had turned the match on its head on 25 minutes, but following a VAR review, Diego Carlos's close-range effort was ruled out off for offside.
In a pulsating opening half, Martinez came to the rescue with a fingertip stop from Semenyo's drive and then clawed away Solanke's shot before Semenyo got clear once again and flashed an effort across goal.
Villa brought on Jacob Ramsey for Zaniolo at the start of the second half, but the Cherries edged ahead within seven minutes of the restart.
Kerkez’s drilled pass was expertly controlled by Solanke, who spun and slammed past Martinez. It was the striker’s seventh Premier League goal of 2023/24, his best return of any season.
Bournemouth nearly added a third just past the hour mark but Martinez reacted superbly to keep out Solanke's close-range effort.
Emery made four further changes in a bid to get back into the match and substitute Jhon Duran was close to a 74th-minute equaliser, but his shot was deflected onto the woodwork by Marcos Senesi and away.
Just when it seemed as though Bournemouth would hold out for a third consecutive top-flight win, Watkins popped up to head home a late leveller to secure a point for Villa.
It was Watkins's 12th goal involvement in his last nine league matches, scoring eight and assisting four.
It means Villa are unbeaten in three matches and are fourth, with 26 points. Bournemouth are also unbeaten in three and are 16th, with 13 points, six above the relegation zone.
Next five PL fixtures
Did you know?
All three of Antoine Semenyo’s Premier League goals for the Cherries this season have been scored inside the opening 25 minutes.
Ollie Watkins’ goal (89:59) was Aston Villa’s latest Premier League equaliser since Keinan Davis netted against West Brom in April 2021 (91:03).
Villa have now conceded in eight consecutive Premier League matches, their longest such run since a sequence of 11 between May and September 2022.