Exeter Chiefs began their Premiership title defence with a defeat as a last-gasp try from Jason Woodward gave Gloucester a 28-21 win on Friday, ending the champions' 17-match unbeaten run in thrilling fashion.
The Chiefs overcame Wasps to claim victory in last season's final, but they were denied at least a share of the spoils in the final seconds at Kingsholm as Gloucester prevailed in Johan Ackermann's first game in charge.
Exeter number eight Sam Simmonds and Gloucester lock Jeremy Thrush traded doubles in the first half, their tries converted by Gareth Steenson and Billy Burns respectively as the two sides went in level at 14-14 at half-time.
Steenson was sin-binned two minutes after the restart for a late tackle on Woodward, but Gloucester were unable to capitalise on their 10-minute numerical advantage.
Ben Morgan gave Gloucester the lead for the first time in the contest in the 56th minute, only to be pegged back nine minutes from time when Olly Woodburn stole the ball from Ollie Thorley and raced down the left to touch down.
Centre Henry Slade converted and had the chance to seal the points with a late penalty following a Gloucester infraction at the scrum, but he pulled his kick wide of the far upright.
Gloucester then worked their way up to the Exeter 22 and, after the ball had been spilled backwards, Billy Twelvetrees found a gap in the defence and offloaded for Woodward to finish out wide to secure a bonus-point win.
INCREDIBLE SCENES AT KINGSHOLM! Bonus point in the bag, and the game is won! #GLOvEXE-- Gloucester Rugby (@gloucesterrugby) September 1, 2017
Elsewhere, Newcastle Falcons made a flying start to their campaign with a 35-8 victory over Worcester Warriors.
Newcastle lead just 10-3 at the break and Josh Adams' try cut the gap to two points seven minutes after the restart, but the hosts subsequently ran in 25 unanswered points to claim a bonus-point success.
Alex Tait, Rob Vickers, Kyle Cooper and Juan Pablo Socino all crossed for the Falcons, while Sonatane Takulua added 13 points with the boot.