Not that the Premiership needs another conspiracy theory, but the wag on a Northampton fans' website who suggested a draw would suit all concerned here very nearly got his wish. A try by Mark Tucker six minutes into added time levelled the scores, and the Saints wing was mobbed by his team-mates in possibly the best example of them acting in concert all afternoon.
When Shane Drahm converted from a tricky angle it sealed Northampton's third successive Premiership victory, while the losing bonus earned by Quins put them a healthy 10 points clear of bottom place in the table. In all probability, both clubs are now safe.
It was a match well suited to a down-and-dirty relegation dogfight. "At this stage of the season, we'll take it," said Northampton's head coach, Budge Pountney. "I'd rather do that than play well and lose."
Arwel Thomas, a blast from the past as far as Wales's Grand Slam generation is concerned, was a lively on-loan item for Harlequins. But two yellow cards for the visitors were heavy handicaps to carry and, at the death, Drahm ghosted through a gap on the blindside of a scrum to send Tucker over at the left corner.
There were, according to the timekeepers afterwards, 10 seconds remaining to play when the scrum was set. Drahm added the extras and punched the air; a gesture replicated by Keith Barwell, Northampton's owner, as he embraced his players on the pitch at the final whistle. From Drahm, whose summer transfer to Worcester was confirmed last night by Northampton, it was an important parting shot.
Pountney was able to join the celebrations after completing a four-week ban from matchday activity for criticism of a referee. He had, wisely, taken up a more dismissive stance in a different war of words this week conducted by the recently departed Saints prop Robbie Kempson, who used an internet column to give a controversial version of the demise of his fellow South African Alan Solomons as coach last November.
Instead, Pountney reserved a strident statement for his team selection, confining his international front-rowers Steve Thompson and Tom Smith to the bench.
It suggested one eye on Friday's daunting Heineken Cup quarter-final at Toulouse. Or perhaps Pountney took a lead from his and Solomons' coaching predecessor, Wayne Smith, who deployed the same tactic for a cup semi-final against Newcastle here three years ago.
Saints were 33-0 up by half-time on that occasion, but lightning did not strike twice. When Thompson, the club captain, joined the fray 11 minutes into the second half, his side were 20-9 behind and struggling.
Quins made their intentions clear in the opening five minutes: three line-out throws, three mauls driven for a combined gain of about 25 metres. The third was dragged down in Saints' 22 and Thomas made it 3-0. It was the former Wales fly-half's first start for Harlequins, having flitted from Swansea to Pau in France to Llanelli Scarlets in recent seasons.
Thomas was prominent, with a high tackle on Marc Stcherbina and a dive on to Saints ball which earned him a stint in the sin-bin after 23 minutes. The upshot from these and sundry other offences was a 9-6 Northampton advantage after three penalties by Drahm and another by Thomas, though in the latter's 10-minute absence Gavin Duffy missed one for Quins.
When Thomas returned, he fed George Harder for a try which reflected poorly on Saints' cover. It was difficult to see how Saints had managed to rouse themselves for this and the preceding victories over Leicester and Gloucester. They are doomed, nevertheless, to finish outside the top five for the first time in seven years.
Eight minutes after the interval Thomas intercepted a pass by Stcherbina and ran 60 metres to the posts, sidestepping John Rudd along the way. But Drahm kicked a penalty and added another as the match moved into overtime when Quins, having withdrawn the impressive Nick Easter from their pack to compensate for the loss of the full-back Tom Williams to the sin-bin, were penalised for dropping a scrum.
Only a crazy sequence of results could yet leave Quins sweating on their visit to Leeds on 26 April, a fixture shoehorned into the last week of the regular season due to the Tykes' involvement in the Powergen Cup final.
"We're ferociously disappointed," said Mark Evans, the Quins chief executive, who intends to stand down as head coach in the summer, perhaps to be replaced by Dean Richards. "But if Leeds don't beat Leicester they're a long way behind."
Northampton: B Reihana; J Rudd, A Vilk, M Stcherbina, M Tucker; S Drahm, J Howard (B Jones, 68); S Emms, D Richmond (S Thompson, 51), R Morris (T Smith, h-t), M Lord (A Codling, 61), D Browne, A Blowers, M Soden (D Fox, 46), C Krige (capt).
Harlequins: T Williams; G Harder, G Duffy, M Deane, S Keogh; A Thomas, S So'oialo; M Worsley (J Dawson, 44), T Fuga (A Tiatia, 29), C Jones, J Evans, S Miall (S Maling, 57), N Easter (H Barratt, 77), T Diprose, A Vos (capt).
Referee: D Rose (North Midlands).