Saints resisted a stirring late fightback from Bath to claim a memorable bonus-point 31-24 victory against one of the pretenders to their Premiership crown.
A penalty try along with efforts from Calum Clark, Christian Day and George Pisi had put Jim Mallinder’s men in command at 31-10 up with 20 minutes to go.
But scores from Olly Woodburn and replacement Nick Auterac, allied with David Wilson’s first-half try, made for a nervy finale at Franklin’s Gardens.
Saints kept their nerve though, resisting a barrage of late pressure to see the game out and end Bath’s 100 per cent start to the season.
It was an epic encounter, illuminated by two huge team efforts and some fine individual displays, with Ben Foden and Jon Fisher in superb form for Saints.
Fisher had only come in at the last minute as Tom Wood was ruled out with a back injury, while James Craig replaced Courtney Lawes in another late withdrawal.
Before the game began there was to be a spine-tingling round of applause for Luis Ghaut, the inspirational 13-year-old, who sadly passed away on Tuesday.
The youngster had motivated Saints on so many occasions before and they were determined to do him proud. By the end, they could certainly have claimed to do that.
Bath were under pressure from the off and Foden, with a trademark surge, ate up the ground before Kahn Fotuali’i’s pass was deliberately knocked on by Luke Arscott.
It would have been a walk-in for Saints had the Bath full-back not intervened, and referee Tim Wigglesworth duly awarded the home side a penalty try.
The visitors’ misery was compounded by Arscott being sent to the bin and Stephen Myler, who was to finish the day with 11 points, landed the simple converstion to take his team into a 7-0 lead.
Saints were on top in every department and after Ken Pisi smashed winger Woodburn into touch, George Pisi drove through the middle and Saints sent the ball right for Clark to score.
Myler lashed the ball through the posts to put his team into a 14-0 lead after a sensational showing in the first 15 minutes of the match.
But Bath, with Arscott returning their number, were soon fighting back, with England fly-half George Ford passing to Wilson, who beat some limp defending and bundled over the line in instalments.
Ford added the extras to cut the gap to seven points, but Saints were soon putting more pressure on in the scrum, handing Myler another three points from in front of the posts.
Bath threatened an immediate riposte as Jonathan Joseph’s silky break had Saints scrambling, but the blue and white wave was stemmed by the referee’s whistle.
But the shrill sound soon rang out against the home side as Wigglesworth penalised George Pisi for not rolling away and Ford made no mistake with the penalty.
Both sides were unrelenting with the ball in hand and it was a frantic battle of a nip and tuck fashion.
Saints missed the chance to make their lead more comfortable as Myler pushed a penalty past the posts, but it had been a fine first half display from Mallinder’s men.
The second period picked up where the first had left off, with the tempo high and the Northampton pack propelling the team forward.
Fisher was everywhere, with Bath struggling to shackle the powerhouse flanker and after he helped carry Saints within touching distance, Foden sent Day over in the left corner.
The noise levels were immense and there was another huge roar to come as Myler superbly converted from the left touchline.
Bath were cracking and Saints were a seemingly inexorable force as George Pisi’s power brought the bonus-point try.
Myler again converted with aplomb and the job appeared all but done, with the away side staring down the barrel at 31-10 down.
Foden wasn’t prepared to relent, though, bundling Woodburn into touch with a huge tackle that drew more appreciation from Gardens faithful.
But Woodburn was to bounce back quickly, latching on to Gavin Henson’s pass to cruise over the line and give his side hope.
Ford’s kick reduced the deficit to 14 points with 20 minutes to go and Saints were suddenly struggling.
Auterac used a driving maul to force his way over the line and Ford’s conversion set up a huge finale, with Bath just seven points adrift.
The men in blue and white were charging forward in search of a try that could provide the chance to level the scores.
A visit to the TMO denied them that try after the pack had again got a sizeable shove on and Saints then had to contend with a series of scrums close to their line.
Bath got the ball out and mounted a late surge towards the line, but Saints stayed strong, won a turnover and saw Wigglesworth call time on an absorbing tussle.
Saints: Foden (Wilson 65); K Pisi, G Pisi, Burrell, North; Myler, Fotuali’i (L Dickson 56); Corbisiero (A Waller 51), Hartley (c), Ma’afu (Denman 60); Craig (Harrison 76), Day; Clark, Fisher, Manoa (Dowson 68).
Replacements not used: McMillan, Hooley.
Bath: Arscott (Henson 56); Rokoduguni, Joseph, Eastmond, Woodburn; Ford, Cook (Stringer 51); James (Auterac 56), Webber (Dunn 56), Wilson (Thomas 54); Hooper (c) (Day 58), Attwood; Fa’osiliva, Mercer, Houston.
Replacements not used: Ewels, Devoto.
Referee: Tim Wigglesworth