A Jonathan Sexton penalty in the fifth minute gave the visitors an ideal start but Munster upped the ante and after Keith Gleeson was sin binned seven minutes later, referee finally lost patience with Leinster's indiscipline and awarded a penalty try.
Leinster struck back with that well worked effort from Dempsey but O'Gara was on the mark again just before the end of normal time to edge Munster in front (10-8). However Sexton landed an injury time penalty to leave his side narrowly in front at the break.
Within two minutes of the restart Munster went ahead again with O'Gara's third successful effort and really from then on it was Munster who took control. Further penalties from the Irish number 10 in the 53rd, 60th and 78th minute gave Munster a victory that moves them ahead of Coonacht ahead of their meting with the westerners on Sunday.
Munster: S Payne; J Kelly, B Murphy, T Halstead, I Dowling, R O'Gara, P Stringer; F Pucciariello (D Hurley), F Heahan (A Kyriacou temp), J Hayes; D O'Callaghan, P O'Connell capt; J O'Sullivan (J Coughlan), D Wallace, D Leamy
Referee: Alan Lewis.