Patrick Schickerling's last-second try helped Exeter come back to beat Premiership champions Leicester.
Exeter were awarded a penalty try midway through the first half before Solomone Kata's try on his debut meant the hosts led 17-6 at half-time.
Hanro Liebenberg got Tigers' first try eight minutes after the break before Charlie Clare put them ahead.
Schickerling, who had had a try disallowed, forced his way over after Leicester gave away a late penalty.
Joe Simmonds' early penalty for Exeter was cancelled out by Freddie Burns' 12th-minute three-pointer.
However, the Leicester fly-half was sent to the sin-bin as Exeter got the first try when he deliberately batted Harvey Skinner's 20th-minute kick behind with the Chiefs fly-half bearing down on the ball.
Exeter defended well and, following a second Burns penalty, Kata went in from 10 metres shortly before half-time after Olly Woodburn's kick set up good field position.
Dan Cole charged down Simmonds' kick to allow Liebenberg to go over as Leicester improved after the break. Clare then touched down after a catch-and-drive from a close-range lineout after an hour.
Exeter upped the pressure, with Schickerling having a try disallowed for a knock-on soon after, while Richard Capstick, Ruben van Heerden and Dave Ewers were all held up over the line by Leicester's defence.
The hosts had Alec Hepburn yellow-carded for a high tackle with 14 minutes left, but despite keeping up the pressure, it seemed as though they would not get past the champions' rearguard.
But Liebenberg was caught offside in the 79th minute, and after kicking to touch and winning the lineout, Schicklerling was forced over from close range after four phases to secure an Exeter win.
Exeter head coach Ali Hepher:
"There was nothing lucky with the win as I thought we were in control for most of that match.
"In that final quarter, we had three hold-ups over the line, a disallowed try, and when the yellow card came for Alec Hepburn, I thought we were up against it.
"However, we kept going at them and got our reward but it was a game we would have lost last year."
Leicester head coach Steve Borthwick:
"The boys are gutted to lose in the last play but we gave them one too many opportunities.
"There were a lot of positives to take from the game as everyone worked exceptionally hard for the club.
"Exeter came out with a specific plan and executed it very well but we adapted by making a few tweaks to be leading on the scoreboard but we missed a few crucial opportunities."
Exeter Chiefs: J Simmonds; Nowell, Whitten, Kata, Woodburn; Skinner, Townsend; Hepburn, Yeandle, Street, Dunne, Gray, Kirsten, Tshiunza, Capstick.
Replacements: Innard, Kenny, Schickerling, Van Heerden, Ewers, J Maunder, O'Loughlin, Cordero.
Leicester Tigers: Ashton; Potter, Scott, Gopperth, Saumaki; Burns, Youngs; Cronin, Clare, Cole, Wells, Snyman, Martin, Reffell, Liebenberg.
Replacements: Taufete'e, Van Wyk, Hurd, Henderson, Cracknell, Wigglesworth, Cokanasiga, Murimurivalu.
Referee: Christophe Ridley.