However, with 10 minutes to play and after a remorseless chase had forced Wes Davies into touch, Harris darted from the base of the scrum and, even though he was buried in the three-man tackle, he managed to sneak the ball out one-handed for Paul Sterling to score the vital try.
Wigan's John Monie called it "a miracle pass" whilst his Leeds counterpart, Graham Murray, said: "He's just a special player. He wasn't in his usual position, but he'd always be the first picked."
Wigan should have had the first point when Anthony Farrell cuffed Tony Smith as be broke through midfield and Phil Jones hit the post with his penalty.
Darryl Powell's deceptive ability to ghost through almost produced an immediate riposte, but he passed to Wigan's Danny Moore rather than one of his own men in support.
That was Wigan's cue to claim the first try, Simon Haughton charging down the left flank and Lee Jackson doing well to stop Moore. Leeds were still overstretched on the right and the ball was moved swiftly across for Mick Cassidy to maintain his prolific try-scoring form this season.
It would have been a misleading scoreline for the visitors to be in arrears at the break and it was Powell who was largely responsible for rectifying the situation, picking up a pass up off his bootlaces and throwing the ball 30 yards for Harris to send Jamie Mathiou over for his first Leeds try in three seasons. Harris added the goal.
Marvin Golden had a try disallowed for Leeds early in the second half before Andy Hay was sent to the sin bin for a late hit on Kris Radlinski, giving Wigan 10 minutes in which to make their advantage pay off. It was Leeds' turn to show their defensive intensity.
Leroy Rivett had a touchdown ruled out before a brief punch-up gave Harris a penalty to stretch the lead. The best was still to come with that wonderful pass to Sterling and Harris added a drop goal near the end.
Wigan Warriors: Radlinski; Robinson, Moore, Connolly, Jones; Florimo, Smith; Cowie, Clarke, Mestrov, Haughton, Cassidy, Betts. Substitutes used: Davies, O'Connor, Reber, Gilmour.
Leeds Rhinos: Harris; Sterling, Golden, Cummins, Rivett; Powell, Sheridan; Fleary, Newton, McDermott, Morley, Farrell, Glanville. Substitutes used: Hay, Mathiou, St Hilaire, Jackson.
Referee: S Cummings (Widnes).
nGateshead have completed the signing of Workington's Australian hooker, Mike Jenkins, to replace their captain, Kerrod Walters, who has returned home. Jenkins, previously with the Newcastle Knights, goes straight into the squad to face St Helens tomorrow.Reuse content