Crossing the finish line in Ulladulla, New South Wales, yesterday, Williams and Kiwi teammates Nelson's Nathan Fa'avae, Stu Lynch, of Auckland, and Queenstown's Chris Forne lived up to their favourites' reputation, beating home more than 90 international teams.
It was the first time Williams had raced with Seagate, which is now a five-time world champion. This victory is its third in a row.
After the 627km, 14-leg race, which required the teams to navigate their way through 50 checkpoints in the Shoalhaven region as they kayaked, mountain biked, trekked, caved and pack-rafted with minimal sleep, it was with weary relief that Williams accepted her new title.
''World champion. I guess it hasn't really sunk in. I guess just finishing the race first is great for starters. I'm just so glad to not be a chink in their armour,'' she laughed.
Seagate captain Fa'avae said Williams adapted well to the established team.
''It's really hard to come into a team at that level and I think Jo did super well. We obviously kind of know what we are doing out there and Jo has to fit into how we race. She's good fun and very, very talented, obviously.
''You don't win these races without lots of tenacity and we were very lucky to have her,'' he said.
Seagate decided to have a short sleep at the penultimate transition and had to move out quickly for the 99km mountain bike leg when eventual second place-getters Adventure Medical Kits arrived in their kayaks.
By the end of the race, which finished with an 18km trek, the United States team was almost exactly two hours behind the Kiwi team.
