Munster trailed 6-0 at the break but reduced the deficit in the opening minute of the second half with a Paul Warwick penalty and took the lead with a superb Horgan try in the 51st minute, Warwick touchline conversion putting them 10-6 up. Horgan try owed much to quick hand from Lifemi Mafi but the veteran Horgan did well to step outside Salesi Sika and then round full-back Chris Wyles before stretching out to score.
At the start of the final quarter, a clean Mike Hercus break was stopped by a great Niall Ronan cover tackle but Munster conceded a penalty and the US went for the line, were denied twice by the uncompromising Munster defence and then had their scrum shunted back as Munster lifted the siege.
And they did so in style, launching an attack down the left touchline that saw Jeremy Manning just denied by a late tackle after he had kicked through. From then on really it was Munster who played all the rugby. O'Sullivan, Denis Fogarty and captain Anthony Foley got through an ocean of work while Mick O'Driscoll,winning his 100th cap also used his experience to good effect.
Munster: Mossy Lawler (J Manning ht); John Kelly (I Dowling ht), Lifeimi Mafi, Kieran Lewis, Anthony Horgan; Paul Warwick, Gerry Hurley (Tomas O'Leary ht); Federico Pucciariello, Denis Fogarty, Tony Buckley; Donnacha Ryan, Mick O'Driscoll; Niall Ronan, John O'Sullivan (James Coughlan 72nd min), Anthony Foley capt.
USA Eagles: Chris Wyles; Salesi Sika, PaulEmerick, Vaha Esikia, Takudzwa Ngwenya; Mike Hercus capt, Chad Erskine; Mile MacDonald, Blake Burdette, Chris Osentowski; Luke Gross, Mike Mangan; Louis Stanfill, Todd Clever, Henry Bloomfield.