Aided by the strong breeze in the first half, Crowley kicked Munster into an early lead before back row Ahern easily barged past Mack Hansen to notch the visitors’ first touchdown in the 12th minute after the fly-half’s clever kick over the Connacht defence.
Connacht cut Munster’s lead to 8-5 in the 21st minute as Jansen finished off a period of pressure but not for the only time, they immediately conceded as Calvin Nash brushed past Santiago Cordero’s weak tackle to set up Casey’s try.
The home side still looked in a strong position when Nankivell received his red card but the only remaining score in the first period was kicked by man of the match Crowley which left Munster 18-5 up at the interval.
Given their second-half wind advantage, Connacht’s prospects continued to look promising when Bundee Aki’s pass to Finn Treacy set up Blade’s touchdown in the 45th minute, with Ioane’s conversion cutting the margin to six points.
But once again, Connacht put themselves under immediate pressure as Shamus Hurley Langton’s handling transgression in a ruck was eventually punished by Crowley’s try after Casey’s lightning quick pass to his Ireland colleague.
Crowley added the conversion and as Munster controlled the remainder of the third quarter, Barron’s close-range finish increased their advantage to 30-12 after 59 minutes.
Helped by Tadhg Beirne’s 61st-minute yellow card which reduced his side to 13 men, Connacht did rally as Jansen notched his second try before Ioane’s score reduced Munster’s lead to 30-24 with eight minutes remaining.
Connacht thought they had notched their fifth try with three minutes left after replacement Dylan Tierney-Martin touched down but the score was ruled out after Aki was adjudged to have illegally taken out Gavin Coombes in a ruck.
With Munster down to 13 again after the yellow carding of Niall Scannell, Connacht had one final chance deep in the visitors’ 22 but Jean Kleyn poached the line-out to seal the visitors’ victory
Connacht: Hansen; Mullins, Gavin, Bundee Aki, Treacy; Ioane, Blade; Duggan, Heffernan, Bealham; Joyce, Murray; Prendergast (capt), Hurley-Langton, Jansen.
Replacements: Tierney-Martin, Buckley, Aungier, Murphy, Boyle, Devine, Hanrahan, Cordero.
Munster: O’Connor; Nash, Farrell, Nankivell, O’Brien; Crowley, Casey; Loughman, Barron, Jager; Wycherley, Beirne (capt); Ahern, Hodnett, Coombes.
Replacements: N Scannell, Wycherley, Archer, Kleyn, Quinn, Murray, R Scannell, Kendellen.
Referee: C Evans (WRU)
