Cardiff Blues increased the pressure on Gloucester coach Bryan Redpath with a 26-25 LV= Cup win at Kingsholm on Sunday.
Ceri Sweeney kicked a last-gasp penalty to see defending champions Cardiff Blues win the re-run of last season's Anglo-Welsh final.
The Blues had won that Twickenham showpiece 50-12 in April, but it was Gloucester who led 16-13 after a frenetic opening half thanks to tries from captain Gareth Delve and flanker Adam Eustace, plus a penalty apiece from fly-half Nicky Robinson and full-back Freddie Burns.
Cardiff's points came courtesy of a Xavier Rush score plus eight points from Sweeney's boot.
Burns and Sweeney traded penalties early in the second stanza before Sam Norton-Knight glided over to put Cardiff back in front.
But two late penalties from Spencer looked to have given the Cherry and Whites a first win in five games, only for Sweeney, who kicked 16 points in total, to hold his nerve in the dying seconds.
Gloucester had brought fly-half Robinson in to face his former club, while head coach Bryan Redpath also recalled the likes of wing Lesley Vainikolo, prop Greg Somerville and number eight Delve following Tuesday night's defeat against Australia.
Adam Eustace came in on the blindside flank with Alasdair Strokosch at openside.
The Blues moved Australian Norton-Knight to full-back with Sweeney at fly-half, while hooker Rhys Williams and prop Taufa'au Filise came into the front row.
The visitors started confidently with both wing Chris Czekaj and centre Gareth Thomas making early inroads to force a penalty for not rolling away that Sweeney slotted over for an early 3-0 lead.
Gloucester enjoyed early dominance at scrum time, and a powerful eight-man shove pushed the Blues off their own put-in, leading to a penalty that Robinson converted to tie the scores.
But Gloucester were soon ahead when the visitors were turned over from a line-out in their 22, with Eustace picked up the loose ball to power over from close range, Robinson striking the post with the extras.
Things soon got worse for the Blues as Robinson's scything break launched another Gloucester assault on the Cardiff line, with captain Gareth Delve dotting down from James Simpson-Daniel's measured grubber kick to make it 13-3.
The Welsh side looked all at sea but they regained their composure, shortly after Robinson left the field to be replaced by Carlos Spencer, to score a superb try.
Captain Rush took a short pass from Sweeney to bulldoze his way through the midfield defence and crash his way over under the sticks, Sweeney adding the simplest of conversions.
Sweeney then levelled the scores as Gloucester were penalised for slowing down ruck ball following a sharp blindside break by scrum-half Richie Rees, but he missed a 33rd minute three-pointer after Strokosch was sin-binned for coming in from the side.
But Gloucester full-back Freddie Burns re-established the hosts' lead after Cardiff were caught offside to give the Cherry and Whites a slender half-time advantage.
Burns extended the lead shortly after the interval with his second penalty, only for Sweeney to narrow the gap with his third penalty.
The Blues reclaimed the lead in the 58th minute when Norton-Knight took the ball in the fly-half position on the blindside of a scrum in the Gloucester 22 to step inside the drifting defence and cross for a try, converted by Sweeney.
The injury problems were mounting for Gloucester as Simpson-Daniel and Burns were forced from the field, the latter being replaced by back-rower Apo Satala.
But Spencer slotted a penalty to trim the lead to one point and then knocked over another three-pointer from 35 metres, after Cardiff's replacement loosehead prop Sam Hobbs was adjudged to have taken down a scrum.
The Blues piled forward in one final surge, seeing a driving maul held up over the line and a 'try' ruled out for offside.
They were rewarded when referee Rob Debney gave a penalty 40 metres out as Gloucester infringed at a last-minute ruck and Sweeney made no mistake.
Tries: Eustace, Delve
Pens: Burns 2, Robinson, Spencer 2
For the Blues:
Tries: Norton-Knight, Rush
Cons: Sweeney 2
Pens: Sweeney 4
Gloucester: 15 Freddie Burns, 14 James Simpson-Daniel, 13 Henry Trinder, 12 Tim Molenaar, 11 Lesley Vainikolo, 10 Nicky Robinson, 9 Rory Lawson, 8 Gareth Delve (capt), 7 Akapusi Qera, 6 Al Strokosch, 5 Dave Attwood, 4 Will James, 3 Greg Somerville, 2 Scott Lawson, 1 Paul Doran-Jones.
Replacements: 16 Darren Dawiduik, 17 Thomas, 18 Pierre Capdevielle, 19 Adam Eustace, 20 Jake Boer, 21 Jordi Pasqualin, 22 Carlos Spencer, 23 Jonny May
Cardiff Blues: 15 Sam Norton-Knight, 14 Richard Mustoe, 13 Gareth Thomas, 12 Gavin Evans, 11 Chris Czekaj, 10 Ceri Sweeney, 9 Richie Rees, 8 Xavier Rush (c), 7 Robin Sowden-Taylor, 6 Ben White, 5 Scott Morgan, 4 Deiniol Jones, 3 Gary Powell, 2 Gareth Williams, 1 Darren Morris.
Replacements: 16 Rhys Williams, 17 Taufa'au Filise, 18 Sam Hobbs, 19 James Down, 20 Josh Navidi, 21 Darren Allinson, 22 Dafydd James, 23 Dai Flanagan.
Referee: Rob Debney (England)
Assistant referees: Paul Dix (England), Don Helme (England)
Assessor: Paul Bridgman (England)
Television match official: Laurie Bryant (England)