Saints were 31-12 down, having shipped four tries, and little was good about their game.
Ben Spencer had pounced for two quickfire scores and the match, and the season, seemed to have unravelled badly.
Saints produced one of the greatest comebacks in the club's history, scoring four tries to snatch a 36-31 victory from the jaws of defeat.
It was as hard to keep up with as it was surreal.
Even at the end, it looked like it had got away.
Bath were on the charge two minutes from time, despite being reduced to 13 men due to a combination of injury and ill discipline, and Saints had to scramble.
They held out a couple of metres from their own line, showing the character that has become their trademark during this late-season play-off push.
And then they worked their way up the field.
Methodical and patient, Saints kept hold of the ball.
Unlike earlier in the game, there was no panic.
They probed and probed and eventually seemed to have worked their way over the line.
But referee Luke Pearce signalled for a knock-on from Juarno Augustus and it seemed Saints would have to settle for a draw, which would have been some result anyway.
As it was, there was one more twist, and it got even sweeter.
The TMO was called upon and Saints were to celebrate as it was ruled Bath had kicked the ball from Augustus's grasp before Mike Haywood picked up to score.
There were air punches galore as the away team savoured a magical moment on a ground where they have sampled so few of them.
Saints had not won at The Rec since December 2015, but that barren run is now over.
And what a way to end it.
They have now claimed four successive league wins, gathering a bonus point on each occasion.
There is real momentum with Chris Boyd's men, who know they must not waste this chance now.
They got a lifeline on Saturday afternoon, or as Boyd called it 'a get-out-of-jail free card'.
And they are unlikely to get any more.
They have to continue to produce this kind of character and this kind of win.
It is what Harlequins did so often last season, striking when their backs were to the wall. It took them all the way to the title.
And, ironically, it is Quins who come calling at cinch Stadium at Franklin's Gardens on Friday night.
It should be some game.
How they rated...
Was unfortunate with one ball that bounced off him that led to a Bath try, but aside from that the full-back produced plenty of class, including a crucial score... 8
Wasn't quite at his sharpest from the off as he made his return to action, but gradually grew into the game... 6.5
Started the scoring for Saints but wasn't really able to get in the game aside from that and was taken off before the comeback began... 6
When Saints finally found their feet late on, this man was at the heart of it, keeping his composure and creating things... 7.5
Has been in fantastic form of late but Bath kept a tight grip on him and he came off before Saints got things together... 5.5
Not an easy day from the tee, but the fly-half did some decent stuff in open play and was helped by a position switch after James Grayson came on... 7
ALEX MITCHELL - CHRON STAR MAN
Had a couple of unlucky moments during the first half, but he was at the heart of all that was good about Saints late on, finishing with a few assists and a score of his own... 8
Got through plenty of work defensively and did what he could to lead his team out of trouble, but came off 15 minutes into the second half... 5.5
Found himself on the wrong side of the referee on a few occasions and it wasn't to be his day... 5.5
Stayed on for the full 80 minutes, helping Saints to transform their fortunes late on in what was a big shift from the tighthead prop... 7.5
Had big boots to fill as David Ribbans was ruled out, but certainly accomplished that with a towering showing that included 15 tackles without a single one being missed... 8
The lock kept plugging away but Bath handled him well, stopping him having a real say in the game before he came off... 5.5
The skipper just keeps producing for his side. He kept his foot on the accelerator right until the end, making big breaks, big hits and more... 8
Worked so hard for his team throughout and even worked during the half-time break to keep himself in the right shape for the second period... 8
Grabbed another score in what was another impressive showing. Even when Saints were struggling, this man was able to have an impact... 8
Replacements (who played more than 20 minutes)
MANNY IYOGUN (for Waller 55)
Added extra energy to the Saints cause and had a good impact in attack as he took the fight to Bath... 7
PIERS FRANCIS (for Collins 58)
Helped to strengthen Saints and came on just as Bath looked to have taken the game beyond Saints. Still able to have a real impact for his side... 7