Four-time winner Andy Birkett, aiming for his second K1 victory, completed the first leg in 2:36:26, finishing 25 seconds ahead of defending champion, Lance Kime.
The two other pre-race favourites, Sbonelo Khwela and Thulani Mbanjwa, both former K2 winners, were lying third and fourth, less than two minutes off the pace.
In the women’s race, O’Donoghue completed stage one in 3:13:57.
The three-time runner-up, chasing her maiden victory in her final race as an elite paddler, was more than 16 minutes ahead of teenager Cana Peek.
The older of the Peek sisters, Jordan, was a further eight minutes behind with two stages remaining.