Manly's bid for a reply was thwarted when Anthony Watmough coughed up possession as the Sea Eagles began a third straight set on the Dragons line, and the arm-wrestle began as both sides struggled to gain an advantage.
Nightingale was denied a try by the video referee in the 23rd minute when he lost the ball over the line, but received more than a touch of good fortune when the man in the video box gave him the benefit of the doubt five minutes from the break.
A deft grubber by Kyle Stanley looked like it had been cleaned up at the back, but Nightingale picked up the scraps with the hint of a knock on before eventually swivelling his way over with the suspicion of a double movement.
A penalty gave Manly the chance to get on the board before the halftime hooter, but their desperation nearly backfired when Jamie Soward raced 90 metres after juggling an intercept only for his touchdown to be denied as the siren sounded for an alleged knock-on.
Pleas from the Dragons for the video referee to be used were ignored by whistleblower Shayne Hayne, replays indicating the try may have had more legitimacy than the earlier Nightingale effort.
The Sea Eagles took little time to work their way back into the game with David Williams scoring after a delightful backline movement, some sleight of hand from Stewart creating an overlap for the winger to go over in the corner.
Stewart almost turned provider again when put into space by Daly Cherry-Evans, but his search for support ended with a pass sailing over the sideline.
Manly upped the ante in defence but the home side withstood the charge before Nightingale made sure of the result with his second.
- AAP