The powerful midfielder scored with a low drive from 15 yards after good work from substitute David Clarkson and a Lee Brown cross set up the chance.
Matt Harrold had fired Rovers in front on 35 minutes, chesting down an Eliot Richards pass before beating Scott Flinders with a well-placed right-footed shot from just inside the box.
But before the cheers had died down Hartlepool were on level terms, striker Luke James picking his spot with a low right-footed shot from a central position just outside the area.
On the brink of half time, man-of-the-match James fired home again from close range after Rovers had made a mess of trying to clear a Jonathan Franks cross.
The visitors had already hit a post through a Franks shot on 31 minutes and there were boos from disgruntled home fans at the interval, but O'Toole saved the day at the end.