Bath Rugby kept their hopes of a play-off place alive with a thrilling one point victory that also inflicted a first Guinness Premiership defeat on Saints for two months.
The result did however all but confirm that Steve Meehan's team will qualify for the Heineken Cup next season, an achievement which looked far from certain before Christmas. It was heartwarming stuff for the loyal supporters and for new chairman Bruce Craig.
It was nip and tuck all the way and each time Bath edged in front, first with a try on the stroke of half-time by Lee Mears, and then when Matt Banahan barged over, Northampton clawed their way back into the lead. But an Olly Barkley penalty regained the advantage and Shane Geraghty was just wide with a dropped goal in the final minute.
"When you win by one point it's always tighter than you would want but it's a win", said Meehan. It could be a very valuable one.
He added: "It was done in a very courageous and characterful manner. I'm delighted with the guys ... great stuff. They're a very competitive side, Northampton."
"We had some opportunities but didn't quite get the ball into space. It was just 72 hours after our last game and we were playing one of the teams who have been top all season, Heineken Cup quarter-finalists and LV Cup winners. We'll be happy with that.
But the situation hasn't changed for us. We've got to win our remaining two games."
A strong effort at the very first scrummage earned a penalty which gave Barkley the chance to open the scoring from 40 metres after just three minutes but Bath fell offside at a ruck almost immediately afterwards and Geraghty brought the scores level.
It was obvious from the outset that the second string players brought into the Saints line-up for the second of three matches in eight days were not there to make up the numbers. They fiercely contested every breakdown, denying the home team the quick ball on which their game thrives.
On 12 minutes, scrum-half Alan Dickens broke from a line-out, combining with Neil Best and Jon Clarke to force Bath on to the back foot. When they moved the ball quickly from the ruck, Paul Diggin came in on the angle from the right wing and Nicky Little stuck out an arm at throat level. Whether instinctive or not, it meant 10 minutes in the bin, although Geraghty missed the simple penalty.
Bath's attempts to get their fast-paced game moving was continually stymied by slow ball and a scrum penalty allowed Geraghty to pin them back into the cricket pavilion corner. With Ignacio Fernandez Lobbe carrying well, Saints kept possession and eventually stretched the 14 remaining players to breaking point, Diggin racing over unopposed in that same corner on 20 minutes.
Bath responded by upping the intensity of their game and Barkley kicked a penalty awarded for a hightackle but when Northampton foiled a dangerous breakout by Luke Watson, Michael Stephenson and Mears by falling offside, Barkley's kick was wide.
The home side were struggling to impose themselves up front but Northampton hooker Brett Sharman undermined his team's efforts by twice throwing long at line-outs straight into the arms of Julian Salvi.
The second time, on his own line with the first half almost over was far more damaging. The flanker was held but Mears picked and was driven over. Barkley's conversion was wide but Bath led 11-8 at the turnaround.
Just six minutes into the second half it was level again as Geraghty kicked a 35-metre penalty, but brought Banahan off the bench as a statement of their intent.
Nick Abendanon nearly scrambled over in the right corner and the ball was swung left where Watson looped a pass to David Barnes on the wing, only for the prop to be forced into touch at the flag by Sharman. The hooker again threw long and Bath were awarded a scrum. Saints conceded a penalty and it was scrum-time again.
A reset led to a free-kick and another scrum saw the visitors marched back. Up went J P Doyle's arm and 11,615 spectators fully expected him to run round behind the posts to award a penalty try but the Irish referee was in lenient mood. Although Saints lifted the siege they conceded another penalty which allowed Barkley to set up posiition deep in the visitors' 22.
As Saints prepared to bring on the 'wrecking ball' that is Soane Tonga'uiha, Bath worked the ball from a ruck and their own 'force of nature', Banahan, stretched a long arm to score at the posts, leaving a straightforward conversion for Barkley. With 20 minutes left, they led 18-11.
But this Saints side, mixed selection or not, were not going to take this lying down and hit back immediately when Michael Claassens fell offside at a scrum and Geraghty pulled back three points. Another offside saw the fly-half land a fourth successful penalty from even further out and when the Bath scrum was adjudged to have stood up in the 69th minute, he put his side 20-18 in front. In nine minutes, his pinpoint kicking had wiped out the home lead.
With Tonga'uiha carrying strongly and Bath using all their subs, they needed a decision to go their way and it came in the 72nd minute when Best was yellow carded for slowing up ruck ball illegally. Mr Doyle's patience had been exhausted and Barkley's kick squeezed inside the left hand post to regain the narrowest of leads.
The remaining minutes were tense in the extreme but whereas earlier in the season Bath were being ambushed at the death, this time the boot was on the other foot. Geraghty sat back in the pocket for the drop goal but fired his attempt a foot or so wide. There was still time for Northampton to launch a last ditch attack but Abendanon launched himself at Bruce Reihana to snuff out the danger.