Well-executed tries from Tiernan O’Halloran and Mike McCarthy helped Connacht establish a 17-6 interval lead in wet and windy conditions.

But quick-fire converted efforts from Alex Cuthbert and Casey Laulala saw the Blues made a tremendous start to the second period and Dan Parks kicked them home.

Connacht had blasted ahead thanks to a try from young winger O’Halloran after just 108 seconds.

They built momentum from a series of rucks and Niall O’Connor’s zippy, flat pass put O’Halloran through a hole and over in the left corner.

Out-half O’Connor added a terrific conversion from out wide but Cardiff enjoyed a good spell in the home half and Parks drove a penalty over from 39 metres out.

A high tackle by Michael Paterson on Henry Fa’afili allowed O’Connor take Connacht into double figures, but the Blues were edging the battle of the breakdown and Parks soon cut the gap to 10-6.

George Naoupu, a late inclusion for the injured Johnny O’Connor, gave away another costly penalty but Parks miscued his kick from in front of the posts.

On the half hour mark, Connacht used their reliable lineout to launch a devastating maul which drove the Blues back over their line and McCarthy was credited with the touchdown.

O’Connor added the extras for an 11-point advantage. Whereas Connacht managed to take their scoring chances, the visitors struggled in that department.

Parks missed a close range penalty that he would have scored nine times out of 10.

A sizzling break from scrum-half Richie Rees should have led to a try and captain Paul Tito knocked on five metres out as the Blues failed to capitalise on a series of promising scrums.

But the Welsh regional side were much more clinical on the resumption. It took just 52 seconds for Laulala’s half-break to open the way for Cuthbert to evade Gavin Duffy’s challenge and score in the left corner.

Parks swung over the difficult touchline conversion and Josh Navidi intercepted a pass near halfway to put Connacht under further pressure.

The ball broke free but John Muldoon’s attempted clearance was blocked and with Connacht’s defence out of shape, Laulala evaded two tackles to score close to the posts.

Parks kicked the conversion for a stunning 20-17 turnaround and it took some time for Connacht to hit back.

Their well-drilled maul forced a number of penalties before Tito was caught not rolling away and received a yellow card.

Replacement out-half Miah Nikora converted the resulting penalty to briefly bring Connacht level.

Both sides struggled to maintain their discipline and Parks sent over the second of two penalty attempts for a 23-20 scoreline.

With Tito back in the pitch, some good clearing out from the Cardiff forwards allowed Parks to drop a goal and take his own tally to 16 points.

With six minutes left, Nikora was short with a 42-metre penalty and Connacht had to endure a frustrating finish as the Blues picked up their fourth win of the campaign.