Ian Taplin's heart sank when the Proisir colt he had such a high opinion of was led out of the ring at the 2018 Karaka yearling sales without reaching his reserve.

But minutes later, the Southland dairy farmer found out he wasn't the only one that rated the colt so highly.

"Trevor McKee came down the chute and told me he wanted to buy him and asked me my reserve," Taplin recalled.

"I asked him who he was buying for and he said 'no, just me' so I said 'how about we go 50-50 in him?' Five minutes after the horse had gone through the ring, we'd shaken hands and the deal was done.

"Trevor said he'd just missed him in the ring because a couple lots ahead of him were withdrawn and he'd been looking at horses in the outside ring."

The horse at the centre of the $20,000 deal was Tappy's One, who goes into Saturday's Gr.3 Winning Edge Presentations Winter Cup (1600m) as a winner of five of his last six starts, among them success in the Amberley Cup (1600m) at Riccarton and last month's Oamaru Cup (1600m).

Should Tappy's One win the Winter Cup, he would earn a $36,000 bonus for winning the double, courtesy of the Oamaru Jockey Club.

"He's every bit as well as he was going into Oamaru. He's still improving," said Taplin, who trains in partnership with his wife Kerry.

"You think 'he can't keep improving, he's just won two Cups' but he honestly is. People were starting to catch up with what he was doing when he won the Amberley Cup but his wins leading into that were first-class too. His times were excellent and his sectionals were phenomenal.

"And then in the Oamaru Cup, he went up and eye-balled that North Island horse (Quiz Kid) and then went and put three lengths on him in the space of 50m."

Tappy's one will be out to honour family stalwarts, both equine and human, in the Winter Cup.

Taplin and his father Sid raced Gr.1 Bayer Classic (1600m) winner Bunker out of the stable of McKee and his son Stephen and Tappy's One traces his roots back to the same family of the McKee-trained 1994 Winter Cup winner Red Baron and another Guineas performer for the stable, Petanque.

"Red Baron is Tappy's One's grandmother's half-brother. Trevor and Stephen had a lot of success with this family," Taplin said.

When Trevor McKee died in 2019, his estate took over his half share in Tappy's One, who had his first nine starts out of Stephen McKee's Auckland stable before transferring in 2020 to the Taplins at Isla Bank, about halfway between Winton and Riverton in Southland.

"He was a certainty beaten in his first couple of starts with Stephen and then he won at Tauranga and qualified for the Karaka Million (1200m at Ellerslie). To me he seemed to falter with about 850m to run and I reckon he might have been galloped on," Taplin said.

"When he got down to us, we found he had a couple of hairline fractures that had calcified and we gave him seven months in the paddock. If it wasn't for Sticko (McKee) being so patient with him, he might have broken down.

"We brought him back up and now he's doing what he's doing. Wait till you see him over 2000m on a good track. Hopefully you'll see the real horse in the Livamol Classic (Gr.1, 2040m) at Hastings."

The Taplins also have Ritani in the Winter Cup, the Makfi seven-year-old mare having run a gallant third to her stablemate in the Oamaru Cup last start.

"We freshened her up and she went a really nice race for fifth at Ashburton and then she just came to the end of her run the other day at Oamaru," Taplin said.

"This was the race we set her for and she's 100 percent fit now. We're hoping she's Tappy's One's biggest danger. We've never had a runner in the Winter Cup before so it's really quite exciting."

The Taplins, who are right in the middle of calving on their 800-herd dairy farm, will also produce Super Tap and Tapdog on the Winter Cup undercard.