The local youngster, who hit the winner at Southampton on Monday, duly obliged again 15 minutes after replacing Dwight Yorke with the leaders struggling to break down the visitors.
Sunderland forged ahead after just six minutes with a well-worked goal superbly finished by Dean Whitehead. Nyron Nosworthy surged forward to find David Connolly who released Whitehead and the Black Cats skipper confidently beat Lee Camp.
The home side should have been further ahead in the 20th minute only for both Whitehead and Daryl Murphy fail to make connect to an inswinging Carlos Edwards corner when well placed in front of goal.
The bumper Stadium of Light crowd however, was stunned in the 23rd minute with a surprise equaliser. Dexter Blackstock surged into the penalty area and when he went down under the challenge of goalkeeper Darren Ward, referee Michael Jones had no hesitation in awarding a penalty, Martin Rowlands converting easily.
Stunned into action, Sunderland surged forward with Jonny Evans failing to make contact in front of goal from a Ross Wallace free-kick and then Damion Stewart was only inches away from turning an Edwards cross into his own goal.
Murphy wasted a great chance when going clear only to shoot past the post and in a frantic finish to the first half, Rangers had Danny Culip and Adam Bolder booked for rash fouls.
Sunderland were forced to reshuffle for the second half when winger Ross Wallace failed to re-appear and after the lively Edwards had twice gone close, the winger played his part in the 76th minute winner.
Substitute Paul Furlong was booked for a challenge on Edwards who played the free-kick square for Leadbitter to shoot through a crowd of players.
Sunderland, unbeaten in 17 matches, can afford to lose one of their three remaining matches and still gain automatic promotion to the Premiership.