An amazing ride by flamboyant jockey Glen Boss has given classy colt Rebel Dane his first Group 1 victory, winning a nail biting Rupert Clarke Stakes at Caulfield on Sunday.

Racing three wide throughout the race, Boss managed to give Rebel Dane cover behind 7yo gelding Linton, and got him through the field to nudge out roughie Fontelina and Solzhenitsyn by a short half head.

Winning trainer Gary Portelli was relieved to finally get the monkey off his back, and capture the elusive Group 1, with a horse that has been ultra-consistent, winning 6 of 10 starts and never finished further back than fourth.

"It's a great relief. Bossy has had the belief that he was a Group One horse and we were hoping he was right," Portelli said.

"People spend a lot of money trying to find a good one, but luckily enough for me ... they and bred an ugly duckling, couldn't sell him, and I got him to train".

"They're great supporters. We've had a lot of luck over the years but nothing at this level and it's great fun.

For Boss, it was his 86th Group 1 victory, and one that was very satisfying.

"He really dug deep and I have nothing but admiration for this colt," Boss said after the race.

Rebel Dane is nominated for the Manikato Stakes at Moonee Valley on October 25, but it's likely he will be freshened up for the Patinack Farm Classic on Cup week.

Solzhenitsyn will head to the Toorak Handicap in a fortnight, where he will look to defend his crown.