With the score at 2-2 in added time, Doyle fired a shot from 25 metres that arrowed into the top corner with keeper Aynsley Pears unable to palm it away despite getting a hand to it.
In a contest between two second-tier teams vying for promotion to the Premier League, Blackburn took the lead in the 21st minute when they were awarded a penalty for Jack Robinson's handball after a VAR check, which was converted by Ben Brereton.
Blackburn's Sam Gallagher then scored an own goal seven minutes later after Max Lowe's shot from range took a deflection off the striker's knee to nestle in the corner of the net.
Gallagher made amends on the hour when he sprang the offside trap to put Sammie Szmodics through as the midfielder restored Blackburn's lead by firing low past keeper Wes Foderingham.
United forward Oli McBurnie then produced a moment of magic in the 81st when he turned a defender in the box, powered past another and slid the ball beyond Pears to make it 2-2 before Doyle, on loan from Manchester City, scored his late winner.
