Two tries from flanker Willie Faloon helped Connacht to a 26-22 victory over Cardiff Blues at Arms Park on Friday.
Although the home side recovered from an early deficit to edge in front midway through the second half, they were unable to hold off the enthusiastic visitors.
The only occasion Connacht had previously managed a win in the Welsh capital was in the pre-regional era, when current coach Eric Elwood kicked them to a 6-3 success over the Cardiff club side in 2001.
Their chances were further diminished shortly before kick-off when Scotland international fly-half Dan Parks, who scored 347 points in 38 appearances for the Blues before crossing the Irish Sea last summer, was ruled out by a hamstring strain.
However the Irish ran in two tries in the first five minutes. Fast handling among the threequarters saw captain Gavin Duffy join the line to send South African Danie Poolman speeding in at the flag. And before the Blues could gather themselves, wing Fetu'u Vainikolo put Faloon through some weak tackling to grab another. Miah Nikora converted the second.
As the home team began to get a foothold in the Connacht half, Rhys Patchell landed a long-range penalty and the fly-half was heavily involved, along with No 8 Robin Copeland, in a move which saw wing Harry Robinson dive in at the left-hand corner after 20 minutes. Patchell was off-target with the conversion.
Nikora responded with a penalty when the Blues backs strayed offside but, despite some welcome adventure by both sides, there was no further score before the interval.
The Blues piled on the early pressure in the second period, but had to settle for a penalty by Patchell after Connacht hooker Jason Harris-Wright, in an offside position, impeded scrum-half Lewis Jones. The punishment was doubled when referee Dudley Phillips showed the guilty man a yellow card.
Patchell slotted over another penalty, but it was soon cancelled out by a similar effort from Nikora and when an aggressive Blues scrum allowed Patchell a further opportunity at goal the teenager pulled it wide.
The Arms Park crowd's disappointment was short-lived, however, as sleight-of-hand by debutant replacement Liam Davies allowed Copeland to gallop over just before the hour mark, putting the Blues ahead for the first time. However but their lead was not to last, with Faloon darting over from a scrum for his second try four minutes later.
Patchell's fourth penalty cut the gap to a single point, but Connacht, sensing an upset, forced the Welsh region back into their own 22 and Nikora was able to add another three points following a Blues infringement to seal the win.
Tries: Robinson, Copeland
Pens: Patchell 4
Tries: Poolman, Faloon 2
Pens: Nikora 3
Yellow Card: Jason Harris-Wright
Cardiff Blues: 15 Chris Czekaj, 14 Owen Williams, 13 Richard Smith, 12 Gavin Evans (c), 11 Harry Robinson, 10 Rhys Patchell, 9 Lewis Jones, 8 Robin Copeland, 7 Rory Watts-Jones, 6 Michael Paterson, 5 James Down, 4 Macauley Cook, 3 Benoit Bourrust, 2 Kristian Dacey, 1 Taufa'ao Filise.
Replacements: 16 Rhys Williams, 17 Nathan Trevett, 18 Scott Andrews, 19 Luke Hamilton, 20 Thomas Young, 21 Liam Davies, 22 Ceri Sweeney, 23 Gareth Davies.
Connacht: 15 Gavin Duffy (capt), 14 Danie Poolman, 13 Eoin Griffin, 12 Brian Murphy, 11 Fetu'u Vainikolo, 10 Dan Parks, 9 Kieran Marmion, 8 Eoin McKeon, 7 Willie Faloon, 6 John Muldoon, 5 Andrew Browne, 4 Michael Swift, 3 Nathan White, 2 Jason Harris-Wright, 1 Brett Wilkinson.
Replacements: 16 Ethienne Reynecke, 17 Denis Buckley, 18 Ronan Loughney, 19 Mick Kearney, 20 TJ Anderson, 21 Paul O'Donohoe, 22 Miah Nikora, 23 Matthew Jarvis.
Referee: Dudley Phillips (Ireland)