Rosie Myers rides Scott Base home ahead of favourite Embellish to win the Karaka Millions 3YO Classic.

Otaki trainer Johno Benner would never question Chris Rutten's eye for a horse, and fair enough, too.

After all, they have combined for a second Karaka Millions victory in four years, after Scott Base stormed home on the outside to win the inaugural Karaka Million 3YO Classic at Ellerslie on Saturday.

It was a brilliant turn of pace from the $22.10 outsider, nudging Embellish on the line and pushing the pre-race favourite into second and collecting the $530,500 winner's share of the million-dollar stake. South Island filly Savvy Coup claimed third after a protest saw Ever Loyal demoted to fifth.

It was another taste of victory for co-trainer Benner and co-owner Rutten, who won the two-year-old classic with Vespa in 2014.

"To be honest at the furlong I stood there and thought 'is this going to happen again?' and yeah, it did," said Benner, who co-trains Scott Base with Holly Wynyard.

"I could see he was coming strong and he's a horse we've had a lot of time for, and he's done it again tonight. We knew he was top-drawer, whether we thought he needed a bit of rain today, maybe, and also maybe a bit further, but he's beaten a very good field. 

Benner said they would sit down with the owners but he felt Scott Base "clearly had further to go" after such a massive performance.

He gave a big nod to Rutten, for his support as well as his eye for a horse.

"He's another horse Chris has bought. He spends his own money, he buys these horses, and he's got an amazing record," he said.

"I never question Chris's eye when it comes to buying horses. Hopefully he buys us a couple more."

"You can't argue with it. It's first class, and congratulations to them [the owners], they've been massive supporters of us and Holly and I probably wouldn't be here if it wasn't for them.

Jockey Rosie Myers, who timed her run perfectly, was also full of praise for Scott Base.

"He's got an amazing turn of foot, it's my second time riding him and I was really impressed the first time I rode him. He relaxed beautifully and he was pretty awesome the last bit," Myers said.

"We were a little but uncertain [how he'd go against this field] but he's shown his class."

Avantage claimed the $550,500 winner's share of the million-dollar purse in the other lucrative race of the night, the Karaka Million 2YO.

A brilliant ride from Opie Bosson saw the $3.10 favourite get the win for the Te Akau syndicate, with stable-mate Al Hasa second and Bocce third.