In front of a bumper Thomond Park crowd Munster’s front eight strangled the life out of the Leinster forwards, forcing the mistakes which allowed man of the match O’Gara to kick the hosts to their fifth straight win.

A lack of discipline up front left Leinster chasing the game in the second half after full-back Girvan Dempsey’s electrifying 19th-minute try had given them an 8-7 lead.

But Munster ground their way to glory as only they can and O’Gara’s 100% kicking display – which saw him grab a personal haul of 20 points – pushed them up to seventh in the table.

With Felipe Contepomi’s knee injury keeping him on the bench, Ireland Under-21 fly-half Jonathan Sexton was handed his first start for Leinster and he did not disappoint in a furious opening.

The St Mary’s College clubman fired over a fifth-minute penalty to put the visitors in front.

However, a clash between Keith Gleeson and Peter Stringer soon saw Leinster down to 14 men as the former walked for his part in it.

Without the Australian-born flanker, Leinster struggled and after 13 minutes they gave away a penalty try as their scrum was completely steamrollered.

O’Gara’s conversion nudged Munster in front yet Leinster, with Brian O’Driscoll and Gordon D’Arcy controlling the midfield battle, bounced back when off a set scrum Denis Hickie broke in off the left flank on a diagonal run and offloaded for Dempsey to charge over for a brilliant score.

Sexton could not deliver the extras and while O’Gara, landing his first penalty, punished some indiscipline from the Leinster pack coming up to the break, a silly yellow card for hooker Frankie Sheahan and Sexton’s second penalty left Munster a man short and an 11-10 deficit to overhaul for the second half.

Almost immediately though, O’Gara pinged Munster in front three minutes into the second half.

Worryingly for both Leinster and Ireland, Dempsey was then helped off the field after sustaining a nasty-looking leg injury.

The peerless O’Gara continued to find his range with his place kicks – he walloped over after 52, 61 and 78 minutes to put the hosts into a double-score lead and his sixth penalty success in injury-time only served to rub salt into Leinster’s already gaping wounds.