Opportunities for Brett Prebble with trainer Ricky Yiu Poon-fai have been scarce since the glory days of champion sprinter Sacred Kingdom, but the Australian jockey hopes a break through on Polymer Win goes some way to restoring confidence in their once strong combination.

Prebble rode Sacred Kingdom to victory seven times, including five Group Ones, but has rarely ridden for Yiu since the horse's retirement at last season.

After getting just five rides for Yiu last term, for one win, Polymer Win was Prebble's second success from 11 rides for the yard this term.

"With Sacred Kingdom towards the end we didn't have a lot of luck, but hopefully this will build a bit of confidence again between Ricky and myself," said Prebble.

Polymer Win was dropping in grade, but Prebble identified a more forgiving surface as key to the five-year-old's improved effort.

"I think he appreciated a little bit of cushion in the track and I was happy when there was rain about. But even with the upgrade, there was a little bit of cushion. He showed a good turn of foot. And even going back up in grade, he might even sneak another win before the end of the season," Prebble said.

Yiu made it a double for the day and 36 for the term when Ambassadorship made it three from 13 in a solid freshman season for the stayer.

"I liked this horse from the moment he came in to my stable," Yiu said. "All he needed was a bit of ground and he has shown that again, winning over 1,800m to go with the two mile wins. He has done a great job and we will put him away now."

Ambassadorship was given a nice ride from Tommy Berry, who smoothly found a one-off spot from gate nine, but admitted he might have pressed the button a bit early.

"I was watching his replays and he had always been just getting to the line late and trying to catch them," Berry said. "I took off a little bit earlier but I got there at the 200m, so he surprised me a little bit. Once he got there he didn't know what to do, he wanted to look around a bit so next preparation he has probably got a bit more improvement left in him."