Warrington all but secured their place in the Super League play-offs but their victory was marred by the dismissal of club captain Paul Rauhihi.

The New Zealand prop received his marching orders 19 minutes from the end for a high tackle on Harlequins forward Daniel Heckenberg but the Wolves held on for a crucial victory.

Instead of closing the gap on sixth-placed Warrington to a single point, Harlequins now face an anxious end to the season as they seek the extra win that will finally save them from any danger of relegation.

Warrington, who will leapfrog Salford into fifth place if the Reds lose by more than 24 points at Hull on Sunday, never looked back after scoring two tries in the first eight minutes.

Left winger Brent Grose set up the first score after only four minutes, intercepting Henry Paul's floated pass and sending the supporting Chris Bridge over.

The Londoners had barely recovered from the shock when the Wolves struck again, right winger Henry Fa'afili pouncing for his 20th try of the season after a sleight of hand by Great Britain centre Martin Gleeson.

Skipper Lee Briers added both conversions to make it 12-0 and Harlequins found themselves under more pressure when full-back Paul Sykes was sin-binned on 13 minutes for holding Grose down in the tackle.

However, the 12-man visitors struck back on 19 minutes when substitute forward Solomon Haumono twisted and turned out of a two-man tackle to plant the ball over the line.

Paul's successful conversion pulled the score back to 12-6 but the superb kicking game of Briers kept the London team pinned back inside their own half for long periods and it was no surprise when Warrington scored again.

Bridge's kick looked to have too much weight on it but centre Toa Kohe-Love never gave up on it and produced a spectacular dive to touch down inches from the dead-ball line.

Briers was off target for the first time but the Wolves added a fourth try three minutes before the break when second rower Logan Swann burst through the first line of Harlequins' defence and sent young substitute Andy Bracek over for his first Super League try.

A heavy downpour in the third quarter meant the scoring slowed up and Warrington suddenly looked sluggish in the change of conditions.

Harlequins rallied when a break from Sykes set up the position for winger Nick Bradley-Qalilawa to score his side's second try, which Paul converted from the touchline.

But Martin Gleeson showed a touch of class to score a fifth Wolves try and Briers added his fourth goal before ex-Warrington back row Paul Noone got Bradley-Qalilawa over for his second touchdown.

Warrington's victory was tarnished when Rauhihi was shown the red card by referee Steve Ganson for a high tackle on Heckenberg and they were forced to endure an anxious final few minutes when hooker Chad Randall scored a fourth try for the visitors, which was goaled by Sykes.

Bridge looked to have wrapped up the scoring in injury time but his try was disallowed because of obstruction.