"I was really nervous leading into this one," said Hurst. "I had a huge break after the Olympics, so I've been fighting my fitness all season. Today was the hardest race I've done all season and to be able to emerge out of the water [and finish] first was just a huge relief."
Hurst was most wary of Radford, who is New Zealand's number one open water swimmer, who also had the challenge of overcoming the removal of his appendix just three weeks ago, costing him valuable preparation time.
The two stuck to each other like glue through the race, with Hurst freely admitting he'd give Radford "a little tickle on his feet" to remind him "I was still around". In the end, Hurst's greater skills on land proved the deciding factor.
"Kane today was exceptional, and to tell you the truth I felt really bad for passing him at the finish," Hurst said. "The run in was very long, and I was always confident that when we got to the beach, I'd get him on the sand."
Despite missing out of the prize, Radford was philosophical about it.
"I definitely left it all out there, gave it everything I could," he said. "Tried numerous times to drop Ky and the other lead guys, just didn't have it out there today."
Radford ended up third, just a second behind Taranaki's Dylan Dunlop-Barrett, a London Olympian in the New Zealand freestyle relay team, and the 2011 King of the Bays winner.
Australian Melissa Gorman won the women's race and $20,000 in cash.
The Queenslander, a former world 5km champion and two-time Olympian, proved far too strong for New Zealand's Cara Baker and Charlotte Webby.
In fact, Gorman swam with many of the elite men the entire way, motivated by the prospect of beating as many as she could. She finished just 11 seconds behind Hurst, a remarkable effort.
"The boys don't like being beaten by the girls," Gorman said. "I'm not sure who it was who sprinted past me at the finish, and I was trying so hard to run, but I'm not really that great on the land."
Gorman said she already had plans for the cash.
"As boring as it sounds, it's just going towards paying the bills. I love swimming and it's just amazing that I can earn a living from it."