Connacht had taken the lead thanks to Matt Healy’s early try but the Blues fought back thanks to six penalties and a drop-goal from the young fly-half.
Following last week’s slender loss to Glasgow Warriors, Phil Davies recalled Alex Cuthbert and Andries Pretorius.
WRU chairman David Pickering and Blues chairman Peter Thomas officially opened the newly installed artificial pitch at the Arms Park.
And a minute’s silence was held for former Cardiff, Wales and Lions great Cliff Morgan, whose funeral took place on the Isle of Wight today.
But it was not a night for running rugby akin to the late great or suited to the new pitch with incessant driving rain.
Former Blues fly-half Parks landed his kick-off straight into touch when play got underway in the Welsh capital.
Both Parks and Patchell missed early opportunities to open the scoring in an error-strewn opening period but Connacht eventually took the lead following a lively snipe from Welsh-born Kieran Marmion.
The former UWIC scrum-half sent the Blues defence scrambling and he released a perfect offload for Healy to dart over.
Parks slotted the conversion but Patchell chipped away with a pair of penalties and a drop-goal to hand the Blues the lead.
But Parks had the last word with a penalty on the stroke of half-time to ensure Connacht took a 10-9 lead into the interval.
The 20-year-old kicked the scoreboard back into action on 52 minutes and the Blues began to establish a stranglehold on the game.
They threatened on several occasions to break though but Connacht held firm in the face of growing pressure.
But Patchell nailed a hat-trick of penalties in the final 15 minutes to secure and then put the result out of reach.Â
