Emma Mason-Smith (open) and Kathy Eggers (open) filled second and third, with O'Hanlon hanging on for fourth.
The Swim Gym Tri (200m swim, 14km cycle, 2km run) was won by David White (open) in 44min 09sec, just over a minute ahead of Abigail Hussey (junior).
In the Broker Webb Risk Services Duathlon (4.5km run, 21km cycle, 2km run), former New Zealand Under-20 rugby loose forward and Magpie Hugh Reed was first into transition after the 4.5km, and held on through the cycle and shorter run to win in a time of 1hr 06min 43sec, more than 2min ahead of Greg Morgan.
The talented Lucy Williams (open), who has resumed training after a lengthy spell on the sideline due to injury, was third overall and first woman home by more than 10min. A former New Zealand triathlon representative, she produced a cycle leg that was quicker than any of the duathlon men.
The perfect weather made for a great start to the series last Sunday, with more than 120 competitors drawn to Pandora Pond. The next Shed 2 series event will be on December 16 when an Olympic distance (1500m swim, 40km cycle, 10km run) will also be included.
Next week the Flaxmere Trust Community Duathlon and Family Fun Relay will take place at Flaxmere Park on Wednesday (enter on the day between 4.30pm and 5.30pm).
This event will be followed on Sunday by the second event in the More FM Bloke Free Triathlon series starting at Clive Memorial Pool at 10am.