Northampton booked a quickfire return to Sandy Park in the Gallagher Premiership play-offs despite suffering a 40-21 defeat against Exeter.
Saints secured a first top-four finish since 2015, clinching the final play-off place after closest challengers Harlequins lost narrowly to Wasps.
Northampton and Quins were tied on 56 points from 22 games, but Saints won one more match and edged through as a result.
IT'S ALL OVER 🤯@SaintsRugby seal 4️⃣th with a losing bonus point after @Harlequins come up agonisingly short 😇@bathrugby seal 6️⃣th with a dramatic late converted try 😱 Unbelievable #GallagherPrem scenes 🥵 live blog: https://t.co/a0GCxwkRpd pic.twitter.com/jxk2actQaT — Premiership Rugby (@premrugby) May 18, 2019
And it means regular season table-toppers Exeter and Northampton will meet again in Devon next Saturday, chasing the prize of a Twickenham appointment with Saracens or Gloucester on June 1.
Saints, who had two players in the sin bin just before half-time, tested Chiefs for large parts of an entertaining encounter and scored tries through Piers Francis, Rory Hutchinson and Cobus Reinach, with Dan Biggar adding three conversions.
But Exeter posted a bonus-point success through touchdowns from Henry Slade, Ben Moon, Don Armand, Matt Kvesic, Dave Dennis and Luke Cowan-Dickie, plus five Joe Simmonds conversions, as they pulled away after being held 21-21 at the break.
Exeter were forced into a late change as prop Alec Hepburn failed a fitness test and was replaced by Moon, while there were opportunities on the bench for forwards Sam Simmonds and Sam Skinner after lengthy injury lay-offs.
England hooker Dylan Hartley, despite being back in full training following a knee injury that has sidelined him since December, did not make Northampton's matchday 23, but fit-again Francis was recalled.
And Saints blasted out of the blocks, stunning Exeter by scoring a try after just two minutes.
Northampton skipper Waller was down receiving treatment for an injury, but his team ran from deep as flanker Jamie Gibson made initial headway before finding full-back Ahsee Tuala, and Francis finished off.
Biggar converted, yet Saints' front-row injury issues would not go away, with hooker Reece Marshall being helped off the pitch and replaced by James Fish.
Away Supporters player of the year @mattkvesic pic.twitter.com/ijd8RJ26GL — Exeter Chiefs (@ExeterChiefs) May 18, 2019
And Exeter wiped out their deficit shortly afterwards, prising open Northampton's defence through centre Ollie Devoto's cleverly placed kick that Slade gathered to cross unopposed.
Simmonds' conversion tied things up, and Northampton then had a reprieve when referee Karl Dickson ruled out wing Olly Woodburn's 45-metre solo effort following a forward pass by Devoto.
But Northampton regrouped, shading the territorial battle as they made ground through wing Taqele Naiyaravoro's powerful running and high-class tactical work by Biggar.
And they were rewarded through a second try after 25 minutes as Tuala again played a pivotal role, setting Reinach free, and he put Hutchinson clear for a converted score that gave Exeter plenty to ponder.
Typically, their response was an impressive one, laying a strong foundation through their forwards and patiently building before Moon touched from close range and Simmonds' conversion hauled Exeter level.
Exeter's forwards were at it again five minutes later, blowing open another defensive hole as Armand touched down and Simmonds kicked another conversion, before Saints' England lock Courtney Lawes was yellow-carded for hands in a ruck.
Saints were hanging on as half-time approached, and Waller followed Lawes to the sin bin following a scrummaging offence, but just when Exeter tried to turn the screw, Reinach intercepted a pass and sprinted 90 metres for a try that Biggar converted.
See you again next week @ExeterChiefs We're into our first @premrugby semi-final since 2015 🙌🏼 pic.twitter.com/AcbxjmxfHb — Northampton Saints 😇 (@SaintsRugby) May 18, 2019
Reinach lasted just five minutes of the second period before he went off after taking a blow to his knee, being replaced by Alex Mitchell, and more Exeter forward pressure resulted in a try for Kvesic.
Northampton could find no way back this time, and Dennis crashed over following a smart lineout move, with Simmonds' conversion taking Exeter 12 points clear.
Simmonds then joined the action, making his first appearance since September, and Cowan-Dickie's score saw Exeter hit 40 points following a dominant second-half display.
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