Three tries in the final 20 minutes of the match sealed a famous 42-30 win for Exeter Chiefs against defending champions Harlequins at Sandy Park.
A Gareth Steenson penalty in the third minute got the ball rolling for the Chiefs and, though Nick Evans responded in kind shortly after, a converted try from Brett Sturgess, scored following a break from Luke Arscott, gave Exeter a seven-point lead inside the first fifteen minutes.
The two teams traded further penalties shortly after before Quins put themselves back into the contest when Evans charged down a Steenson kick to score an unconverted try.
Steenson made partial amends when he struck a penalty just before half-time, although Ugo Monye's converted try on the hooter cut the Chiefs' lead to just two points.
Many expected the tide to turn in the second period but Exeter got off to the perfect start when Ben White burst over from close range following an eye-catching length-of-the-pitch break.
Quins hit back just before the hour when Karl Dickson crossed after Rory Clegg's interception and the conversion from Clegg put the visitors back within two.
The match was still anyone's for the taking in the final 20 minutes and it was Exeter who were able to take proceedings by the scruff of the neck.
A quickfire brace of tries from Jason Shoemark - the second converted by Steenson - put real daylight between the sides for the first time and there would be no Quins comeback this time.
Clegg's penalty in the closing stages pegged the Chiefs back temporarily, but Sireli Naqelevuki ensured the hosts had the final word when he bulldozed his way over the line to send the Sandy Park faithful into raptures.
Tries: Sturgess, White, Shoemark 2, Naqelevuki
Con: Steenson 4
Pen: Steenson 3
Tries: Evans, Monye, Dickson
Con: Evans, Clegg 2
Pen: Evans 2, Clegg
Exeter: 15 Luke Arscott, 14 Ian Whitten, 13 Phil Dollman, 12 Jason Shoemark, 11 Matt Jess, 10 Gareth Steenson, 9 Haydn Thomas, 8 Richard Baxter(c), 7 Ben White, 6 Tom Johnson, 5 James Hanks, 4 Dean Mumm, 3 Carl Rimmer, 2 Simon Alcott, 1 Brett Sturgess.
Replacements: 16 Neil Clark, 17 Ben Moon, 18 Chris Budgen, 19 Aly Muldowney, 20 Dave Ewers, 21 Will Chudley, 22 Ignacio Mieres, 23 Sireli Naqelevuki.
Harlequins:15 Mike Brown, 14 Seb Stegmann, 13 Matt Hopper, 12 Jordan Turner-Hall, 11 Ugo Monye, 10 Nick Evans, 9 Karl Dickson, 8 Nick Easter, 7 Chris Robshaw (c) 6 Tom Guest, 5 George Robson, 4 Olly Kohn, 3 James Johnston, 2 Joe Gray, 1 Mark Lambert.
Replacements:16 Rob Buchanan, 17 Joe Marler, 18 Will Collier, 19 Charlie Matthews, 20 Maurie Fa'asavalu, 21 Danny Care, 22 Rory Clegg, 23 Ollie Lindsay-Hague.
Referee: Martin Fox
Assistant referees: Peter Huckle, Gareth Copsey