"We are talking about you spending four grand on airfares to get here and see the Kiwis driving off with the trophy. It doesn't look terribly good."
They took the advice, headed back to Australia so were not on hand to watch the Oracle skipper turn his team around, while sending Barker's TNZ into a tailspin.
"So, there you have it: neither my father nor (Uncle Ron) thought Oracle could win the Cup."
While improvements to the boat, a major crew change and improved sailing all contributed to the fightback, Spithill reveals how he used a press conference to start turning the screws on Barker and co. by planting doubt in their mind.
After Team New Zealand's eighth win, he told the media: "...imagine if these guys lost from here. What an upset that would be. I mean, they've almost got it in the bag. I've been involved in some big fight-backs, some big challenges, and faced a lot of adversity, and that's the kind of thing I'd love to be involved in. We feel we've got just as much chance to win this and we're going to do everything we can."
Spithill explained in his book: "I sensed this was a situation I could use to put unexpected pressure on the Kiwi team: they had everything to lose. I don't think such a thought had ever previously entered their minds, but now it had. This was a fight to the end..."
The combative Australian said says "I don't believe there is luck in sailing" but concedes this is what saved Oracle, when the Kiwis were robbed of Cup victory on race day 10, when light winds forced the first race to be abandoned.
With racing cancelled the next day, thus allowing more practice sessions, Oracle finally started to master foiling upwind with the score at 3 - 8.
Spithill says: "Once we could sail on the foils upwind, we were off like a startled gazelle. Upwind foiling would prove a game changer.
"At the end of this practice day, I went home feeling the best I had in weeks. I always had faith that we could come back but after that day's practice session, I really knew it."