The eagerly awaited duel between rival England captains Chris Robshaw and Tom Wood was ruined by torrential rain as Northampton inflicted a first defeat of the Aviva Premiership season on Harlequins.
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A match that should have provided the stage for Robshaw and Wood to demonstrate to England head coach Stuart Lancaster who deserves to be at the helm this autumn instead deteriorated into a war of attrition at Twickenham Stoop.
The back rows are competing for their international places and the leadership duties against Australia, Argentina and New Zealand in November, but Lancaster's mind will be none the clearer after this arm-wrestle.
The heavy rain that began falling in the afternoon continued throughout and it took the strength of Northampton's giant Wales wing George North to help break the deadlock with the score tied at 6-6.
North, the Premiership's marquee signing of the summer, rode two tackles as Saints thrust deep into Harlequins' half.
A set-piece later Luther Burrell spun the ball wide to Jamie Elliot, who combined with James Wilson to send the Kiwi outside centre storming over for the decisive try in the 63rd minute.
Stephen Myler converted and kicked two penalties, but it was a harrowing night for his opposite number Nick Evans, the former New Zealand fly-half who landed only two of six penalty attempts.
The victory came at a cost, however, as England lock Courtney Lawes departed early in the second half and later appeared in the stands with strapping around his left thigh and knee.
Northampton threatened early on but were held up over the goalline after driving from a line-out, and when Joe Marler was penalised at the ensuing scrum, Myler kicked Saints ahead.
Two missed penalties from Evans hampered Quins, but full-back Mike Brown almost broke through the defence.
Marler, England's third choice loosehead, was in a combative mood, tussling first with Calum Clark and then opposite number Tom Mercey to earn a warning from referee Andrew Small.
Robshaw, who was rested for the summer tour to Argentina enabling Wood to take a post he filled with distinction against the Pumas, dug Harlequins out of a hole by tidying up at the back of a line-out
It was then Brown's turn to pin Northampton back after breaking free down the left wing, evading England rival Ben Foden in the process.
Saints scrum-half Kahn Fotuali'i, making his full debut, defied the dreadful conditions by switching on the afterburners to create space, only to run into touch.
Evans and Myler missed penalties and then the second half opened with Evans missing a third, before he finally nudged Quins ahead six minutes after the interval.
Lawes departed before Myler drew Northampton level and with Evans missing once again, substitute Ben Botica was brought on - only to blunder with a chance from in front of the posts.
Water was spraying from the players' boots as North began the move finished by Wilson, and Quins suffered further when number eight Nick Easter was sin-binned for a professional foul.
Moments later Myler followed Easter into the sin bin for a deliberate knock on, but Saints had already done enough to clinch victory.