The Falcons are now the overwhelming favourites to go down from the Gallagher Premiership this season
Newcastle clung on to their place in Gallagher Premiership for another day at least after Leicester fell to an ugly 23-19 defeat by Harlequins.
The Tigers needed two points from the penultimate round of the regular season to condemn Newcastle to relegation, but fell short on a hard-fought evening at the Stoop.
Victory over Gloucester on Saturday will allow the Falcons to survive until the final weekend when they host Bristol, but they would still remain overwhelming favourites to go down.
Harlequins replaced Northampton in fourth to lift their hopes of securing a semi-final, in the process ending their five-match losing run in the Premiership.
Flanker Alex Dombrandt was a constant threat in the carry, prop Kyle Sinckler rampaged around the pitch and scrum-half Danny Care marked his return from a hamstring injury with a lively display, but it was an evening of few highlights.
Replacement lock Semi Kunatani delivered the knockout blow seven minutes from time when he scooped the ball from a ruck and galloped through a gigantic hole to finish under the posts.
All of Leicester’s points were delivered by the boot of George Ford until Mike Fitzgerald drove over three minutes into overtime, securing a bonus point that could yet be critical in condemning Newcastle to relegation.
Former Australia captain James Horwill led out Quins in his final home appearance before retiring at the end of the season and his team were quickly into their stride though a piercing attack launched by Mike Brown.
It took six minutes for the first try to come, strong carries from Dombrandt and Horwill at a line-out creating the chance for Care to cross from close range.
Two penalties by Ford kept Leicester in touch and a period of dominance followed as Quins spent increasingly lengthy spells defending in their own 22.
For all their possession, the Tigers could not breach the try-line but as half-time approached their prospects improved when opposition number eight Jack Clifford was sent to the sin-bin for a dangerous tackle on full-back Telusa Veainu.
Back chat from Quins cost another 10 metres and although the home side rallied superbly at a threatening line-out, Leicester’s assault continued with waves of attacks forcing a penalty that was landed by Ford.
Veainu departed for a head injury assessment a full two minutes after he had been flattened by Clifford, but he passed the test.
A stilted start to the second half produced few thrills but a pair of Smith penalties propelled Quins back in front and Leicester’s chances faded when Dan Cole conceded a penalty just as his side were building a head of steam.
The visitors lacked cohesion and their lack of threat was summed up when Ford sent an attacking kick straight into touch.
And typically they were at fault for the try that finished them off as they left a ruck unguarded, allowing Fijian giant Kunatani to touch down.
The last word was had by Leicester, however, as replacement second row Fitzgerald used his bulky frame to force his way over and secure the losing bonus point.