He beat Australian defending champion Clint Robinson in a thrilling finish to the tough 56km race.
Faced with tough flat and windless conditions for the Kaiwi channel crossing between Molokai and Oahu, the title race quickly turned into a two-horse affair between Robinson and 2009 champ and current K1 World Marathon Champion McGregor.
McGregor made a charge with six kilometres to go and led by almost a minute as he approached the turn at the fabled China Wall, where he was able to surf the swell close to the shore thanks to the mild ocean conditions.
Robinson, however, put in a serious last ditch effort to reel in McGregor as the turned into the estuary that houses the finish, and in the final two kilometres he ground McGregor’s lead down to thirty seconds.
Australians Cory Hill and Jeremy Cotter filled third and fourth places respectively before current world series leader and Molokai debutant Jasper Mocké crossed the line to take fifth, just ahead of another Australian stalwart Martin Kenny.
Twelve-times champion Oscar Chalupsky finished tenth, with the Durban North brothers Ross and Bruce Poacher the first double skin crew home in eleventh.
The women’s race was won by Rachel Clarke from Lisa Wadling, and the double ski crew of Sally Marks and Alena Greensill.