Wallace bundled his way over the line for Munster's second try of the game with help from fellow forwards James Coughlan and Mick O'Driscoll in the 59th minute, O'Gara converting.
BBC: Munster 22-16 Ospreys
2.
Ulster looked sharp from the start and capitalised on a turnover on seven minutes when Nigel Bradey's pass, which appeared to be forward, sent Wallace clear to the line.