St Helens and Wigan both finished with 12 men after Louie McCarthy-Scarsbrook and Frank Paul Nuuausala were sin-binned for their part in a scuffle which could see further repercussions.
Saints won the fiercely-contested Super League derby 23-4 on Friday (Saturday AEST) in front of a season's-best crowd of 20,049 at the DW Stadium in Wigan.
All but seven of the 27 points came in the first half when Keiron Cunningham's men took their chances to establish a 16-4 lead before demonstrating magnificent defence to keep their hosts scoreless for 70 minutes.
Tempers which simmered throughout finally erupted into an ugly incident late in the match which saw mid-season NRL recruit Nuuausala sin-binned in his home debut along with McCarthy-Scarsbrook.
Saints ended the game on a high when hooker James Roby took Luke Walsh's pass to score his side's third try, with Percival kicking his fifth goal from as many attempts.
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In Hull, halfback Marc Sneyd grabbed 12 points against his old club as the hosts secured top spot in Super League with a 28-20 win over Salford.
The Red Devils made Hull FC fight all the way and led 20-18 until Sneyd went over for a try nine minutes from time.
