Dukedom settled at the tail-end of the field before he picked up ground across the top and he finished willingly under premiership leader Lisa Allpress to score at odds of 25-1.
"This is huge for me. I'm only in my second season of training," Cole said. "Lisa gave him a gun ride and they got the luck when they needed it."
Allpress had committed to the Trentham ride after she had partnered Dukedom to a previous third in the group two Great Northern Guineas at Ellerslie on New Year's Day. "He got caught in a tight spot last time and didn't really get clear," she said.
Allpress ensured Dukedom got the clear air he required on Saturday and they finished too well for the southerner Son Of Maher and Rangipo, with Xtravagant a weakening fourth after making the running.
"Once I got to the outside I thought here we go," Allpress said. "He's still a bit raw and he's going to improve."
Dukedom will now be given a short break before he takes in the group two Avondale Guineas on his way to the group one BMW New Zealand Derby.
- NZ Racing Desk.