Spithill suffered the elbow injury before the America's Cup finals but kept it a secret.
"About five weeks out from the Cup I tore tendons in my elbow. I kept it pretty quiet and used cortisone injections to get through it."
The chirpy Aussie yachtie has strong ties to New Zealand and he was thrilled both host nations made the final.
"It's hard not to be completely wrapped up in the whole thing," he said. "It is kind of cool, too, that here we are going head-to-head in an ultimate battle and both sides want nothing more than to win, but pretty soon after we will be commemorating Anzac Day together. It's a really cool thing."
While his countrymen would be their usual confident selves heading into the match, there was no chance they would take the Black Caps lightly.
"No way. They will have full respect for them. They have got some awesome athletes in that [New Zealand] team. There has been some awesome cricket from everyone but New Zealand has been the form team up until now. Hopefully that will change, obviously."
Another famous Aussie battler is feeling even more generous towards us.
Australian singer-songwriter Paul Kelly, whose classic odes to the game include Bradman and Leaps and Bounds, which references the MCG, told the Weekend Herald: "Actually, I wouldn't be unhappy if you guys won."