Gloucester overhauled a 17-point deficit to cement their place in the Gallagher Premiership play-offs with a 27-23 victory over West Country rivals Bath.
The Cherry and Whites were left stunned by a first-half blitz that saw Ruaridh McConnochie and Tom Dunn score tries in the opening 20 minutes.
But Danny Cipriani sent Josh Hohneck over on the stroke of half-time before Ruan Ackermann's try breathed hope into Gloucester.
Cipriani then sparked a pair of unstoppable backline moves for wingers Henry Purdy and Tom Seabrook to crash over in either corner to complete the stunning comeback.
The triumph, coupled with Worcester's defeat of Sale, all but guarantees the hosts' place in the top four with three rounds of fixtures remaining.
Former Gloucester star Freddie Burns orchestrated the perfect start for the visitors on his former stomping ground.
The hosts somehow kept Bath at bay after three minutes of possession, until Burns spotted McConnochie in space on the right flank and picked him out with a pinpoint crossfield kick for the opening score after only four minutes.
The former Cherry and Whites playmaker converted from out wide and landed a penalty five minutes later to leave a shell-shocked Gloucester with a 10-point deficit to overturn.
Things got worse when Dunn surged through the heart of the defence and over the line, with a little help from Sam Underhill.
Gloucester finally sparked a comeback in the third minute of extra time when Cipriani gave a no look pass to tighthead Hohneck, who crossed the line to score.
Beno Obano boosted the Gloucester cause when he flew into a tackle around the fringes of a ruck without using his arms to earn himself a yellow card.
And the comeback was well and truly on after 45 minutes when Gloucester made their advantage count at a scrum to earn a penalty. Willi Heinz took it quickly and sent Twelvetrees powering into a pack of Bath defenders before Ackermann exploited the space to surge through a gap and over the line.
Twelvetrees added the extras to cut the gap to three points but Burns extended it back to six with a 45 metre penalty after Jaco Kriel took McConnochie out in the air.
However, a scintillating backline move brought the Cherry and Whites back to within a single point after 56 minutes.
Cipriani looped around Mark Atkinson and fired a cut-out pass to Matt Banahan, who sprinted into open space before finding Purdy with the scoring pass.
Burns found the target with a snap drop goal, but there was no stopping the free-flowing Gloucester attack from completing the comeback.
Cipriani fixed the defence and put Banahan on the outside of the defence, the giant full-back gave another scoring pass to Seabrook, who skipped past Joe Cokanasiga to put Gloucester 24-23 in front.
Twevetrees added a penalty to his tally, and Gloucester saw out the final moments to seal a dramatic comeback win at Kingsholm.