It was a tale of two fly-halves at the Recreation Ground as Saints all but cemented their place in the Aviva Premiership top two with a 19-19 draw against Bath.
Stephen Myler landed 14 points for Jim Mallinder’s men and also executed a silky offload to tee up Jamie Elliott for a second-half score.
But 19 points from George Ford, who grabbed a cutting second-half score, ensured the spoils would be shared.
The game ended with a chorus of boos from the home fans, who saw referee Matthew Carley overrule his touch judge on the award of a late Bath penalty.
Carley decided there had been no offence in a Courtney Lawes tackle and blew the whistle to end an enthralling encounter.
Lawes had earlier been sin-binned, while Bath prop Anthony Perenise was also yellow-carded with two minutes to go, giving Myler the chance to earn his team a draw.
A draw seemed a fair result as Saints’ dominance in the first-half was mirrored by a strong Bath showing in the second.
And it means Northampton will now be sure of a home play-off semi-final should Leicester fail to beat Sale at the AJ Bell Stadium on Saturday afternoon.
Referee Carley was to begin the night as he finished it, irking the Bath faithful as he awarded a penalty at the scrum.
And Myler got his fine evening off to a good start, making the kick to give Saints the lead.
The away side were the ones playing with the most vibrancy early on, with Bath struggling to clear their lines under pressure.
Saints were swarming all over their opponents, playing the game almost exclusively in the home half.
Bath were having to put their bodies on the line, time after time, and paid the price for it as hooker Rob Webber was forced off with a nasty-looking knee injury.
Saints were switching the ball from side to side, desperately trying to penetrate the home line, but Bath were holding firm.
That pushed Myler into attempting a drop goal, but his effort drifted to the right of the posts.
Saints had earned just three points from a dominant opening 23 minutes, during which Bath failed to venture into the opposing 22.
But after finally mananging to put some pressure on, the home side levelled the scores through a Ford penalty.
Saints had the chance to strike a rapid reply after Samu Manoa was taken out in the air by Dave Attwood, but Myler’s kick drifted wide.
The fly-half soon had another chance thanks to strong work at the breakdown from Lawes and, this time, Myler made no mistake from the tee.
But Bath were using the little territory they enjoyed well and Ford again restored parity with a well-struck penalty.
The England man wasn’t so accurate soon after, though, as he dropped back into the pocket and pushed his drop goal attempt wide.
Bath started the second half with the dogged determination which had become their theme during the first, but this time it was in the attacking half.
And after putting the squeeze on Saints, Ford was given another penalty chance, which he spurned to draw groans from the home faithful.
But the No.10 soon made amends as, with the penalty coming, he sidestepped Lawes and raced over to claim the try.
With the extras safely added, Bath had their tails up, the noise levels increasing every time a player in blue and white got his hands on the ball.
Saints needed to stick together and they did, immediately returning to enemy territory and knocking loudly on the door.
They eventually blew it down, with a sublime piece of skill from Myler, who released the ball out the back of his hand to Elliott, breaking Bath’s resistance.
Myler made the conversion to level the scores and Saints quickly called for the cavalry, sending for four fresh forwards to boost their charge.
Bath, meanwhile, were hit by the loss of another hooker, replacement Ross Batty, to injury, with loosehead prop Nathan Catt taking up the No.2 berth.
And he was immediately into the action, helping to win a penalty at the scrum, with Ford landing it to put his team back in front.
Saints were hit by yellow peril soon after as Lawes was sin-binned for taking Bath wing Anthony Watson out off the ball.
But the home side were at a disadvantage at lineout time, with flanker Guy Mercer taking the throwing responsibility.
Tom Wood immediately stole one before a knock-on from Elliott saw George Pisi’s try chalked off.
Saints were soon level, though, as they got their revenge at the scrum and Myler landed the resulting penalty with aplomb.
It was to make for an enthralling final 10 minutes, with Lawes returning from the bin to boost the Saints ranks for a final push.
Ford threw hit boot at the ball with a drop goal attempt that was horribly skewed, but he put Bath ahead with three minutes to go with another penalty.
Saints had to respond quickly, and they did, as Anthony Perenise was yellow carded for a dangerous tackle on Mike Haywood and Myler kept his nerve to level the scores.
And that was how it was to stay, despite Carley’s late call, which saw him exit the field to a backdrop of jeers.
Bath: Abendanon; Watson (Agulla 73), Joseph, Devoto (Henson 71), Banahan; Ford, Young (Stringer 63); James, Webber (Batty 18 (Catt 55)), Wilson (Perenise 55); Hooper (c), Attwood (Day 71); Fearns, Mercer, Houston.
Saints: Foden; K Pisi, G Pisi, Burrell, Elliott; Myler, Fotuali’i; A Waller (Denman 71), McMillan (Haywood 55), Ma’afu (Mercey 55); Manoa (Craig 55), Lawes; Clark (Dowson 55), Wood (c), Dickinson.
Replacements: A Day, Wilson, Collins.
Referee: Matthew Carley