Saints profited from two blunders by Wigan’s veteran full-back Matty Bowen to claim the spoils in an absorbing Grand-Final re-match to go top of the First Utility Super League.
Wigan lead 10-8 at the break and the game was still finely poised at 14-14 when Joel Tomkins scored their third try on 50 minutes but the champions finished strongly to claim a 30-14 victory that enabled them to leapfrog Leeds at the top of the table.
All three of Saints’ second-half tries came gift-wrapped by their visitors, two of them after Bowen fumbled kicks from St Helens’ bloodied captain Jon Wilkin, who shrugged off a head injury to lead his side’s assault at a highly-charged Langtree Park.
Hooker James Roby was also at the heart of a battling Saints performance after defying a hand injury to play the full 80 minutes.
Most eyes had been on Ben Flower as he faced St Helens for the first time since his dismissal in the opening moments of October’s Grand Final for punching Lance Hohaia and the Welsh international prop shrugged off the boos to give Wigan a solid start with a series of strong runs.
Flower made way after 16 minutes for the return of winger Joe Burgess, who had been helped off after only two minutes after catching a stray boot to the head.
That meant a re-shuffle, with John Bateman joining fellow second rower Joel Tomkins in the centres, but it did not adversely affect the visitors, who went in front when Dan Sarginson, switched to the wing in Burgess’ temporary absence, accepted George Williams’ cut-out pass to cross for the game’s first try.
Matty Smith added the goal and the Warriors were good value for their 6-0 lead after looking much the livelier side throughout a brutal opening quarter.
The home crowd were incensed by a high tackle from Wigan captain Sean O’Loughlin on his opposite number Wilkin while Saints’ heavyweight prop Mose Masoe incurred the wrath of the Wigan fans with a late flop on hooker Michael McIlorum.
At least it took the attention away from Flower, who was roundly booed with each touch of the ball.
Saints were slow to find their groove but they discovered a purple patch to score two tries in a three-minute spell to go in front.
Quick hands enabled centre Jordan Turner to get winger Adam Swift over at the corner on 28 minutes and, after stand-off Travis Burns had kept the pressure on with a 40-20 kick, an almost identical move from the resulting scrum saw Turner force his way over the line himself.
Mark Percival was unable to add either conversion and Wigan regained the lead two minutes before the break when Saints passing broke down near their opponents’ line and Burgess, showing no ill-effects from his head knock, pounced on the loose ball and sprinted 90 metres for an opportunist score.
The lead changed hands for a third time time in 12 minutes when Bowen was deceived by the bounce following Wilkin’s grubber kick and Burns dived on it for St Helens’ third try.
This time Percival was on target with the goal attempt to make it 14-10 but it was all square 10 minutes into the second half when Tomkins finished a slick handling move to cross for Wigan’s third try.
Back came Saints and, when the visitors conceded a penalty for interference in the ruck, Percival kicked his side back in front and they went on to dominate the final quarter.
Turner looked certain to score his second try before losing the ball in Josh Charnley’s tackle but Saints pulled clear on 65 minutes when Bowen made a hash of dealing with Wilkin’s high kick and McDonnell was gifted an easy try.
The game was gone when Sarginson’s wayward pass near his own line was pounced on by Wilkin for a fifth try and Percival added the conversion before wrapping up the scoring with a late penalty.