The name on everyone's lips at the sell-out Cork venue was 20-year-old Keith Earls who, starting at outside centre and finishing at fullback, pocketed two tries while other fringe players like Billy Holland and Donnahcha Ryan gave McGahan a selection headache ahead of Edinburgh match in the Magners League next Friday.
London Irish's early adventure was thwarted by strong Munster defence, the home side lifting the siege and turning over the ball twice inside four minutes.
There was also an edge to the early exchanges with events boiling over after just five minutes when a scuffle broke out near the touchline. Tony Buckley and Chris Hala'Ufia were called aside by Alan Lewis and binned, but the referee's action had the effect of settling the game down.
Munster posted the first try on 11 minutes, a score created by Anthony Horgan. The veteran winger hacked ahead inside his own half, gathered before laying off smartly to Neil Ronan who sprinted 35 metres unopposed to the line.
The extras were added by Paul Warwick, who was instrumental in setting up good field position in the build-up to the Heineken Cup holder's second try. Awarded a five metre scrum, Munster opted to pick and drive. Donnacha Ryan and John O'Sullivan made the hard yards before Frankie Sheahan picked form the base of ruck and drove over with Warwick making it 14-0.
Irish struck back in the 24th minute when Ireland A captain Bob Casey gathered a wayward Munster throw on the home side's five metre line and had the easy task of dotting down.
Aussie Peter Hewatt landed the conversion to bring his side back into the match.
Munster's third try involved some wonderful backline play, an insight into McGahan's expansive philosophy. Doug Howlett and Mick O'Driscoll combined to set up the impressive Barry Murphy who sprinted to the corner.
But, on half time, Delon Armitage silenced the crowd, intercepting a Warwick pass to run 70 metres to the line and leave it stand 21-14 at the break.
McGahan emptied the bench for the second half with the frontline internationals playing a huge part in bossing territory and possession. The intensity levels never waned and Munster never lost their shape with Rua Tipoki making some splendid midfield incisions.
Report: Ed Newman/Irish Examiner