A nerveless display of kicking by fly-half Andy Dunne gave Connacht a priceless 20-18 win over the Scarlets in the Magners League at Galway Sportsground on Friday.
Rhys Priestland looked to have stolen the points with a penalty as the clock ticked over 80 minutes, but Dunne gave Connacht the win with a penalty on the stroke of full-time.
The Irish province continued their impressive home form - they have lost just one of their last six games at the Sportsground - but they had to do it the hard way.
Scarlets fly-half Rhys Priestland almost got the visitors out of jail as he landed four second-half penalties, including an injury-time effort which nudged the Welsh region into an 18-17 lead.
But Connacht, seeking only their second win over a Welsh side since October 2006, bounced back to hand Andy Dunne an 84th-minute penalty chance which he took with great aplomb.
A massive rainstorm before kick-off had threatened to ruin this clash but it eased off and allowed Connacht's energetic pack to take the initiative behind busy half-backs Dunne and Conor O'Loughlin.
An early offside saw Dunne kick the hosts into the lead and penalty kicks were the order of what was a scrappy first half lacking in any real creativity.
A tired-looking Scarlets outfit, missing the likes of Stephen Jones, Dwayne Peel, Alix Popham and Vernon Cooper, struggled to make any impact and two Priestland penalties just about kept them in touch.
Two more place-kicks from Dunne had maintained Connacht's advantage and, in the 34th minute, scrum-half O'Loughlin swooped to claim the game's only try as he blocked down a clearance kick from Priestland on the visitors' 22 and won the race for the touchdown.
Llanelli, 14-6 down at the interval, upped the ante on the restart and soon had the better of territory, although strike runners Morgan Stoddart and Regan King were kept in check by a determined Connacht defence.
Priestland and Dunne traded further penalties but mistakes crept into Connacht's game as the half wore on and the Scarlets cut the gap to 17-15 thanks to their number 10's accurate kicking.
Ireland international Gavin Duffy let his side down by failing to field a garryowen and missing a crucial touch as Llanelli launched a spirited fightback.
Stung late on by the Dragons on New Year's Day, Phil Davies' men edged ahead thanks to Priestland's sixth penalty success, however Connacht had enough time to hit back for a win which leaves them four points clear of Ulster at the foot of the table.
Pens: Dunne 5
For the Scarlets:
Pens: Priestland 6
Connacht: 15 Gavin Duffy, 14 Matt Mostyn, 13 Daniel Riordan, 12 Mel Deane, 11 Aidan Wynne, 10 Andy Dunne, 9 Conor O'Loughlin, 8 Colm Rigney, 7 Jonny O'Connor, 6 Mike McCarthy, 5 Andrew Farley (c), 4 David Gannon, 3 Robbie Morris, 2 Adrian Flavin, 1 Brett Wilkinson.
Replacements: 16 John Fogarty, 17 Ronan Loughney, 18 Michael Swift, 19 Ray Ofisa, 20 Conor McPhillips, 21 Tim Donnelly, 22 Darren Yapp.
Scarlets: 15 Morgan Stoddart. 14 Dafydd James, 13 Matthew Watkins, 12 Regan King, 11 Mark Jones, 10 Rhys Priestland, 9 Liam Davies, 8 Nathan Thomas, 7 James Bater, 6 Simon Easterby (captain), 5 Scott Macleod, 4 Adam Eustace, 3 Bruce Douglas, 2 Matthew Rees, 1 Phil John.
Replacements from: Deacon Manu, James Hayter, Dafydd Jones, Jonathan Edwards, Gavin Cattle, Ceiron Thomas, Nathan Brew, Garan Evans, Daniel George
Referee: Andy MacPherson (Wales)
Touch judges: Peter Fitzgibbon (Ireland), Leo Colgan (Ireland)