Munster have continued their unbeaten start to the 2011-12 Heineken Cup with a 26-10 win over Castres at Thomond Park.
O'Gara added three penalties to his tally over the next 15 minutes, either side of Castres flanker Yannick Caballero crossing the line to set up Pierre Bernard's conversion that kept the French outfit alive at the break.
Bernard kicked Castres back to within six points of the home side after the restart. However, O'Gara responded in kind.
With just over ten minutes to go, Munster's Wian du Preez crossed the line and allowed O'Gara to add to his total and kick the Irish outfit 16 points ahead.