Saracens had too much for Saints while Exeter saw off Sale, Leicester beat Wasps and Quins pipped Bath.
Sale Sharks 14-20 Exeter
Exeter remained top of the Gallagher Premiership table and provided a hammer-blow to Sale Sharks' top-four hopes following a 20-14 triumph at the AJ Bell Stadium.
The Sharks started well, often forcing the Chiefs into reverse in the loose, but mistakes were their undoing and the West Countrymen benefited, touching down twice through Ollie Devoto and Don Armand.
With Gareth Steenson adding a penalty and conversion, Exeter held a 15-0 advantage at the interval, which proved to be enough to claim the win.
Although Sam James and Will Cliff crossed the whitewash for Sale, Sean Lonsdale's try helped the visitors remain at the Premiership summit.
Bath 29-31 Harlequins
Nathan Earle's try snatched a 31-29 bonus-point victory for third-placed Harlequins with the last move of the game after Bath fought their way back from being 14-0 down in the first 11 minutes.
Joe Marchant scored a brace for Quins while Chris Robshaw and Alex Dombrandt also went over with James Lang adding the extras.
For Bath, Jonathan Joseph, Nathan Catt and Ross Batty went over with Rhys Priestland adding 14 points with the boot but it was the second game in succession that Bath had thrown away victory in the dying seconds, after an equally agonising 27-26 loss at Northampton last Saturday.
Leicester Tigers 19-14 Wasps
Leicester Tigers secured a vital Gallagher Premiership victory as they held out for a 19-14 win over Wasps with a huge defensive effort at the end of a gruelling encounter at Welford Road.
Fly-half Joe Ford put in a tremendous performance to get all Leicester's points with a try, four penalties and a conversion, while wing Marcus Watson scored two first-half tries and fly-half Rob Miller converted twice from the touchline for Wasps.
Saracens 36-17 Northampton
Saracens inflicted more misery on Northampton as they claimed a 36-17 win in the Gallagher Premiership at Allianz Park.
The hosts, who have now won their past nine matches against the Saints and have scored more than 50 points against them on all four occasions last season, cruised to victory to ensure their winning run at home is now 17 games in all competitions.
Sean Maitland scored twice with Nick Tompkins, David Strettle, Tom Woolstencroft, a penalty try and two conversions from Ben Spencer adding to their tally.
Northampton went into the game in good form, having won four of their past five league matches, rising to fifth in the process.
But they had few answers to the power and accuracy of Saracens, only scoring twice, through Reece Marshall and skipper Lewis Ludlam.