"It was very heart-in-mouth stuff," said Cleeve. "He's a C5 runner over the middle distance and I thought he could use that natural ability to find the pace early, sort of having that advantage.
"But those other dogs came out running, there was a wee bit of jostling, and we certainly had a fair bit of work to do."
Did Cleeve think that his charge would be able to get there?
"No. I thought Thrilling Rogue was travelling too good and had too big a break. But slowly, he just kept taking ground.
"We're absolutely thrilled with the boy today."
Cleeve and his partner Gaylene Turnwald have spent many years perfecting their breeding lines, and Know Keeper's star quality is no accident.
"In New Zealand, I possibly think there's too many sprint races and that's something that Gaylene and I have sort of focused on, is what can we do to influence our breed to maybe get the 500m races for a start and then longer if possible," said Cleeve.
"So, we made the decision early on in our breeding that we would only breed from C5 middle distance performers and hopefully those sorts of bitches would throw on the genetics that make them run 520m, and match them up with a sire.
"With Know Keeper, his mother (Know Jinx) ran third in a Silver Collar five years ago and we labelled her pretty early on as one of our broodies. And the sire, Know Class, we actually sent to Australia for the Sandown Cup, where he won a heat and then was unplaced in the final.
"It's a big thrill to breed any dog of the quality to be competing in these group races, whether it be a staying race, a middle distance or a sprint."
Cleeve has been involved in the industry for around 40 years, and Know Keeper's victory on Sunday marked Cleeve's first ever Silver Collar win.
"I'd never won one of the big three; the New Zealand Cup, the Auckland Cup or the Silver Collar. I've placed in all of them, and after 40 years, you sort of think, 'Am I ever going to win one?!'"
Cleeve confirmed that the Nationals (New Zealand heat at Addington on August 11, Australasian Final at Wentworth Park on August 27) is a future target for his staying sensation.
"We'll find out what the immediate staying races are after the Nationals. Whether he goes to New South Wales and races there after the Nationals, or whether we look to Melbourne will depend on the calibre of the races.
"He's done a really good job for us and perhaps he deserves a shot at the big time."