Dunedin led narrowly 9-7 at halftime at Hancock Park and Pirates kept the score close until Dunedin broke away in the last 20 minutes.
The other standout player for Dunedin was fullback Liam Edwards, who scored 20 points to become the fourth player to reach 100 points this winter.
University A scored two late tries to get a bonus point 36-29 win against Green Island at Miller Park. Japanese import Aki Jamadu scored two tries on the wing for the students.
Wing Bryce Morgan scored two of Kaikorai's four tries when it got a bonus points 30-21 win over Zingari-Richmond at Bishopscourt.
Taieri just managed to hold on for a 24-20 win in the Roy Neiper Trophy match at Bathgate Park.
Alhambra-Union went on a scoring spree in the second spell to beat Harbour 34-18 at the North Ground.
The scores were: University A 36, Green Island 29; Kaikorai 30, Zingari-Richmond 21; Taieri 24, Southern 20; Dunedin 45, Pirates 19; Alhambra-Union 34, Harbour 18.
