More late agony for Saints as Exeter snatch dramatic win
Saints suffered more late heartache on home soil as Joe Simmonds slotted a penalty a minute from time to earn Exeter Chiefs a precious 34-31 win.
Chris Boyd's side had led 28-17 after flying out of the blocks at the start of the second half.
But after Alex Mitchell was yellow carded for a deliberate knock-on, tries from Jack Yeandle and Olly Woodburn put Exeter ahead.
Piers Francis was able to level the scores with a huge penalty, but Simmonds had the final say after Exeter earned a shot at goal.
The defeat was Saints' third in succession in the Gallagher Premiership and their play-off hopes are now starting to fade as they remain ninth in the standings, eight points behind fourth-placed Exeter.
The black, green and gold had headed into the game against Rob Baxter's side after losing 22-21 to Sale Sharks on the previous weekend.
And Exeter looked to have compounded that misery eight minutes into the game as Tom O'Flaherty intercepted a Fraser Dingwall pass and raced home.
But the effort was ruled out for a clear pull on the shirt of Alex Coles, who was running forward to support George Furbank when the full-back broke over halfway.
Saints were handed a penalty, and James Grayson, starting for Saints for the first time since November, did superbly to land it from long range.
Exeter levelled things up almost immediately as a Josh Hodge run caused panic in the Saints half, allow Simmonds to slot the resulting penalty.
Saints responded with some lovely play, starting with Furbank's tidy chip, but after some fantastic offloading from left to right, the ball was eventually spilled into touch at the last by Matt Proctor.
The home side kept coming though and after Exeter were caught offside, Grayson made it 6-3.
But Saints were soon hit by a sucker punch as the dangerous Hodge beat Tom Collins and cruised in unopposed for the score.
Simmonds converted, but Saints weren't deterred and they pieced together a superb score 10 minutes before the break.
Mitchell made the initial inroads before Juarno Augustus grabbed the ball, beat a man and then delivered the perfectly-timed offload for Proctor to score.
Grayson slotted a lovely, flat conversion and Saints led 13-10.
But Exeter were immediately on the front foot, booting a penalty to the corner and using their power as Dave Ewers forced his way over.
Simmonds converted as the see-saw nature of the game continued.
Saints headed in at half-time 17-13 down, but they were ahead little more than a minute into the second period as some superb work from Dingwall opened the door for Collins to score.
Grayson converted and Collins was soon flying forward again, bursting from inside his own half and putting Exeter under pressure, lifting the noise levels in the process.
Saints earned a penalty and Grayson did the rest, giving his side a six-point lead.
The momentum was totally with the hosts and after they absolutely demolished Exeter at the scrum, Augustus charged in for the score.
Grayson missed the conversion and Saints knew they needed to keep their foot on the gas to avoid heartache in the final 20 minutes.
Exeter thought they'd scored through Santiago Grondona with 18 minutes to go but the referee and TMO did not see a clear grounding and Saints escaped.
But they were soon down to 14 men as Mitchell was penalised for a deliberate knock-on.
And Exeter took immediate advantage as replacement hooker Yeandle powered over after a lengthy period of pressure.
Simmonds converted superbly and he was soon doing some stellar work with a crossfield kick, planting it in the path of Woodburn, who gathered and scored in the same motion.
It was a quite amazing try and it gave Exeter the bonus point.
Simmonds converted from the touchline and the game had completely turned, with Saints now 31-28 down with only nine minutes to go.
Mitchell came back on just as Saints had been awarded inside the Exeter half, and Francis opted to go for goal against the wind, landing it superbly to level the scores.
But after O'Flaherty had wriggled through the Saints defence, the hosts conceded a penalty, which Simmonds slotted to win the game for his side.
Saints: Furbank; Skosan, Proctor (Francis 60), Dingwall (c), Collins; Grayson, Mitchell; Iyogun (Waller 50), Haywood (Fish 61), Painter (Hill 50); Ribbans, Ratuniyarawa (Nansen 60); Coles, Matavesi (Tonks 63), Augustus.
Exeter Chiefs: Hodge; Woodburn, Whitten, Hendrickson, O'Flaherty; J Simmonds, S Maunder (J Maunder 57); Hepburn, Innard (Yeandle 49), Schicklerling (Street 49); Kirsten, Jenkins; Ewers, Capstick, Grondona.
Referee: Craig Maxwell-Keys