Gloucester came from behind to avoid an embarrassing opening European defeat with a 19-17 win against the Dragons at Kingsholm on Friday.
Nicky Robinson rescued the English side from the abyss with a late penalty that extinguished an impressive display from the in-form visitors.
The Wales international fly-half kicked fourteen points, but his match-winning strike did not arrive until five minutes from time.
The Dragons had been on course for a famous win - their first in eleven attempts against English opposition in the Heineken Cup.
They outscored Gloucester 2-1 on tries after fly-half James Arlidge and number eight Joe Bearman claimed first-half touchdowns.
But Robinson, a summer signing from Cardiff Blues, proved the difference, landing four penalties and converting flanker Akapusi Qera's 25th-minute touchdown.
Robinson kept his nerve when several Gloucester players cracked under pressure, yet qualification for the last eight from Pool Two remains open to question.
They have to play French giants Biarritz home and away, in addition to visiting the Dragons and Glasgow, suggesting the European campaign could prove a hard slog.
But head coach Bryan Redpath will just feel relieved to collect a win - the manner of it was almost irrelevant - after a testing five weeks scarred by suspensions, numerous yellow cards and three Guinness Premiership defeats.
Gloucester launched their European campaign without banned forwards Olivier Azam and Adam Eustace, but skipper Gareth Delve returned after serving a two-week suspension.
Injured trio Mike Tindall, Olly Morgan and Eliota Fuimaono-Sapolu were also absent, while the Dragons went into battle without captain Tom Willis, so lock Luke Charteris led the Welsh side.
Gloucester, with just two Premiership wins behind them from five starts this season, endured a predictably nervous opening.
Errors abounded on both sides, especially in the tactical kicking department, but close-quarter exchanges proved fierce, a fact underlined when Bearman went off for treatment to a head wound.
The Dragons were combative in all areas, yet they fell behind after 25 minutes when their defensive organisation was smashed by Gloucester juggernaut Lesley Vainikolo.
The England wing blasted through two weak midfield tackles, enabling him to free centre Tim Molenaar, who marked his European debut by finding Qera with a scoring pass.
Robinson added the extras, but Gloucester found themselves under pressure from the restart and it took some superb defensive work by Delve to prevent Charteris from touching down under a pile of bodies.
It was a brief reprieve though, and the Dragons drew level when Arlidge sliced through a gap from first-phase ball for a try that he also converted.
Gloucester knew they were in a dogfight, and with the Dragons' confidence growing, they sensed further points before half-time.
And a second try arrived, this time scored by Bearman, who was the beneficiary of a deft inside pass from scrum-half Wayne Evans as Gloucester wilted all too easily.
A second Arlidge conversion took the Dragons 14-7 clear, leaving Gloucester searching for answers that did not appear readily available.
They needed two Robinson penalties in quick succession to raise hopes among the majority of an 11,800 crowd, before he edged Gloucester ahead with a superb 48-metre strike.
All the Dragons' earlier good work was in danger of unravelling, but they almost reclaimed the lead, only for a long-range Arlidge penalty attempt to bounce back off the post.
But Arlidge made no mistake just two minutes later, finding his range from 40 metres as the Dragons prised a 17-16 advantage approaching the final quarter.
Mistakes were plentiful, and it was difficult not to sympathise with gifted Gloucester runners like centre James Simpson-Daniel and full-back Tom Voyce, who hardly received a pass.
The Dragons had to keep their nerve as they found themselves in the unfamiliar position of a possible Heineken Cup away win, a feat they have achieved just twice before.
But another Robinson penalty - his fourth - edged a tense affair, leaving the Dragons desolate and Gloucester breathing a huge sigh of relief.
Pen: Robinson 4
Tries: Arlidge, Bearman
Gloucester: 15 Tom Voyce, 14 Charlie Sharples, 13 James Simpson-Daniel, 12 Tim Molenaar, 11 Lesley Vainikolo, 10 Nicky Robinson, 9 Rory Lawson, 8 Gareth Delve, 7 Akapusi Qera, 6 Alasdair Strokosch, 5 Alex Brown, 4 David Attwood, 3 Greg Somerville, 2 Scott Lawson, 1 Alasdair Dickinson.
Replacements: 16 Darren Dawiduik, 17 Paul Doran-Jones, 18 Pierre Capdevielle, 19 Peter Buxton, 20 Andy Hazell, 21 Dave Lewis, 22 Freddie Burns, 23 Jonny May.
Dragons: 15 Jason Tovey, 14 Aled Brew, 13 Tom Riley, 12 Ashley Smith, 11 Richard Fussell, 10 James Arlidge, 9 Wayne Evans, 8 Joe Bearman, 7 Gavin Thomas, 6 Dan Lydiate, 5 Luke Charteris, 4 Robert Sidoli, 3 Nigel Hall, 2 Steve Jones, 1 Alistair McKenzie.
Replacements: 16 Duane Goodfield, 17 Hugh Gustafson, 18 Peter Bracken, 19 Lewis Evans, 20 Hoani MacDonald, 21 Danny Lee, 22 Shaun Connor, 23 Martyn Thomas.
Referee: Peter Fitzgibbon (Ireland)
Assistant referees: David Keane (Ireland)), Sean Flannery (Ireland)
Television match official: Tony Redmond (Ireland), Laurie Bryant (England).