Jameka has scored a decisive win in the VRC Oaks to give trainer Ciaron Maher his second consecutive victory in the Classic at Flemington.

Eight months ago Ciaron Maher declared Jameka would win the VRC Oaks and on Thursday the filly delivered the trainer his second in two years.

After she won the Group Two Sires' Produce in March, Maher told her owners he believed he had the filly to emulate Set Square's 2014 Oaks.

Maher built his reputation with a string of top-class jumpers and an unlikely Emirates Stakes win in 2007 with 100-1 chance Tears I Cry.

It took him seven years to win his next Group One race with Set Square but he is now making it a habit after two with Srikandi last season and now No.5 with Jameka.

Despite her win over her male counterparts in the Vase at Moonee Valley, punters opted for Saturday's Wakeful Stakes winner Ambience as the $4 favourite ahead of Jameka ($4.60).

At the end of the 2500m, the margin was decisive with Jameka beating Honesta ($8.50) by 2-1/4 lengths with Ambience third another 1-1/4 lengths away.

"There's nothing better than winning a big race during the Flemington carnival. That's what it's all about," Maher said.

"I'm just thrilled to be able to do it for the second year with very high-quality horses.

"It's a great job by the team. Really good owners, long supporting and its great to win a Group One for them."

Among the owners is Col McKenna who has been waiting 15 years to celebrate a Group One win.

"We went out last night to celebrate beforehand in case it didn't happen," McKenna said.

"How good a trainer is Ciaron Maher?

"He'll win a Melbourne Cup and it could be with this filly."

Honesta's trainer John Thompson was left lamenting the filly's outside barrier and the slow pace.

"She had to go back from the bad barrier and they went too slow up front for her," he said.

For Oliver it was Group One win No.107 on a day when Jim Cassidy retired on 104 after his Oaks mount Dawnie Perfect was scratched with swelling in a leg.

"I had a lot of faith in this filly's ability," Oliver said.

"She had a faultless preparation. She was just going too easily a long way from home."

Oliver was one of the many jockeys who paid tribute to Cassidy on the day and also said his thoughts were with the family of 22-year-old Australian rider Tim Bell who died on Tuesday night after a fall from a high-rise building.

"To lose such a talented young rider ... the whole jockey community is grieving," he said.