Condon's initial introduction lasted less than a minute when he came on as a 63rd minute replacement for Dave Kilcoyne only to be yellow carded by referee Alan Rogan
Munster drew first blood with a Cusack penalty after 6 minutes but Ulster levelled ten minutes later with a Niall O'Connor penalty and took the lead with the impressive Ian Whitten finishing off a move started by Timoci Nagusa.
Cusack reduced the deficit with his second penalty before adding the extras to a well worked try finished by Riordan.
Just on half time a bout of Munster pressure ended with a try under the posts for Varley.
Munster: Danny Riordan; Felix Jones, Tom Gleeson, Scott Deasy,Denis Hurely; Declan Cusack, Paul Rowley; Dave Kilcoyne, Damian Varley, Stephen Archer; Ian Nagle, Dave Foley; Billy Holland, Tommy O'Donnell, James Coughlan capt.
Ulster Ravens: Jamie Smith, Timoci Nagusa, Johnny Sheils, Ian Whitten, Tommy Seymour; Niall O'Connor, Cillian Willis; Patrick McAllister, Declan Fitzpatrick, Adam Macklin; Neil McComb, Ryan Caldwell; Chris Napier, David Pollock, Tamaiti Horua. Replacements: Ryan Fisher, Justin Fitzpatrick, John Burns, Alistair Birch, Ian Porter, Luke Marshall, Chris Cochrane