A late try by wing Matt Jess earned Exeter Chiefs a well-deserved losing bonus point after a fiercely-fought battle played in sweltering conditions yesterday.
The Chiefs looked set to travel home with nothing to show for their considerable efforts after a contest which swung one way, then the other.
They trailed 12-0 after 27 minutes, but led 16-12 early in the second half, only for Saints to pull eight points clear at 24-16, before Jess popped up with his third try in two matches.
Exeter even went searching for a match-winning score in the dying seconds, such is the never-say-die attitude of Rob Baxter's team, but it was not to be.
However, if you had offered the Chiefs six points from their opening two matches before the season had started, they would surely have bitten your hand off.
The major downside to the afternoon for Exeter was what looked like a serious right ankle injury to Samoan winger Josh Tatupu, who was stretchered off in the 50th minute, having only just returned from a broken ankle which saw him miss the second half of last season.
It was generally not a good day for the kickers, with respective fly-halves Ryan Lamb and Ignacio Mieres missing early penalty chances.
Luke Arscott, recalled at full-back for Exeter, looked in rock-solid form and put in two great tackles on opposite number Ben Foden and winger Ken Pisi in the early stages, but it was Foden who initiated the game's first try in the 15th minute.
He fielded an Exeter kick on halfway and ran it back at the Chiefs before feeding Russian international winger Vasily Artemyev, who was stopped just short of the line by a superb tackle from Tatupu, but the ball popped up for lock Christian Day to score.
Lamb fluffed the conversion, and 11 minutes later, Mieres was off target with a 40-metre penalty opportunity.
Saints scored again when Lamb roared through a gap in Exeter's defence, and after good work by Foden and Artemyev, England flanker Phil Dowson touched down in the left-hand corner, and Lamb converted from the touchline to put Saints 12 points in front.
Memories of last season's 33-3 record Premiership defeat for Exeter at Franklin's Gardens came flooding back, but the Chiefs responded straight away.
A piece of individual brilliance by Tatupu saw him sidestep Artemyev in a one-on-one challenge, and even though the Russian did very well to get back and tackle the winger, the Samoan passed inside for centre Phil Dollman to gallop in beside the posts, with Mieres converting to make it 12-7.
Exeter lost lock Aly Muldowney to a rib injury, but Lamb's high tackle saw Mieres add another three points, and on the stroke of half-time, referee JP Doyle used the newly-introduced extended Television Match Official system to take another look at a tip tackle by Northampton's South African number eight GJ Van Velze on the Exeter scrum-half Will Chudley, and handed him a yellow card, though it could just have easily been red.
Mieres slotted the resultant penalty, and Exeter had a 13-12 interval advantage, which the Argentinian increased to four points with another successful kick in the 52nd minute, soon after Tatupu had been injured.
Exeter thought they had scored another try through scrum-half Will Chudley, after a series of pick-and-go drives in the Saints' 22, but the referee deemed he had been held up just short of the line, when video evidence perhaps suggested otherwise.
Northampton's driving maul was causing Exeter a lot of problems, and the hosts enjoyed a period of dominance midway through the second half which gleaned them two tries in a seven-minute spell.
A missed tackle allowed replacement centre Luther Burrell to race through to edge the hosts 17-16 ahead after 56 minutes; and then England hooker Dylan Hartley also crossed after the Saints had kicked a penalty to the corner and won the line-out ball.
Replacement fly-half Stephen Myler converted the second of those two tries, and Saints were suddenly 24-16 ahead, with a try-scoring bonus point in the bag.
In between those two scores, Exeter had lost No.8 Richard Baxter to a leg injury, but with Northampton dominating territory, there seemed little prospect of getting a score to snatch a bonus point of their own.
However, with two minutes remaining, Saints' Plymouth-born flanker, Rhys Oakley, was sin-binned for a trip, Exeter fought their way into the Saints' half, and Fijian replacement Sireli Naqelevuki created space with a lovely dummy before sending Jess racing away to the corner for a vital touchdown.