Wigan Warriors' battle to avoid relegation from the engage Super League took another huge step forward with a narrow victory over fellow strugglers Harlequins at the Twickenham Stoop.

Both teams scored four converted tries, but the difference was the penalty goal kicked by Michael Dobson three minutes into the second half.

But the Warriors would have had grounds for complaint had the result gone against them, because both of Quins' first-half tries were highly controversial.

After 18 minutes, Solomon Haumono appeared to be stopped short of the line, but attempted to ground the ball over the whitewash. Referee Karl Kirkpatrick went to the video referee, who took an age to give the Samoan the benefit of the doubt and the try. Henry Paul converted.

Wigan hit back with two tries in seven minutes to take the lead approaching the half-time hooter.

First, Chris Ashton took Danny Orr's pass to cross near to the posts. Then, in the 32nd minute, Brett Dallas picked off a pass from Mark McLinden, intended for Nick Bradley-Qalilawa and he returned it 50 metres for a try behind the posts.

On the stroke of half-time, Pat Weisner tried to go over but lost the ball on the line. The hooter went, but referee Karl Kirkpatrick went to the video referee, who ruled a penalty try, the tackle by Dobson being ruled illegal and stopping a score.

Having fallen behind to Dobson's second-half penalty, Quins regained the lead when Joe Mbu ran onto Karl Temata's short pass and blasted his way to the line. Paul's conversion gave Quins a four-point lead, but they could not hold onto it.

After 54 minutes, Mark Calderwood raced onto a grubber kick, dribbled forward and dived on the ball in the in-goal area. Six minutes later, Calderwood turned provider for Ashton to score his second try.

Harlequins cut the deficit to two points when McLinden picked up a ball dropped backwards by Zeb Luisi as he was being forced into touch and ran past two startled Warriors to touch down. The video referee had his easiest call of the night to give the try.

But it was not enough for Quins. They did not really pressure the Wigan line and it was the Warriors who looked more likely to score.