Gerald Ryan had owner Gerry Harvey to thank after Mrs Onassis raced to victory in an Oakleigh Plate she nearly didn't run in.

Mrs Onassis improved on her brilliant record over the 1100m of the Group One sprint in a dramatic race that changed complexion before it even began with the scratching of favourite Barakey.

The unbeaten Perth sprinter Barakey was withdrawn on veterinary advice after diving forward in the barriers and tried to get down under them.

None of that mattered to Ryan, who had set Mrs Onassis for Saturday's feature sprint at Caulfield for four months but nearly pulled the pin earlier in the week.

Mrs Onassis had turned in a couple of "below par" gallops on wet tracks in the past couple of weeks and Ryan was doubting her fitness for the Oakleigh Plate last weekend.

He even rang Harvey's racing manager Claire Bird with his concerns about running but got a return call on Monday with the advice from Harvey.

"Gerry said `don't give up so easy'," Ryan said.

"'You set her for the race in November. Work her in the morning and see what you think'.

"She worked that well on Tuesday morning so we thought we'd give it a go."

Mrs Onassis ($16) sat outside the leader Adebisi during the run before hitting the front at the 200m mark.

The five-year-old powered to the post to win by a length, holding off the Queensland challenge with Facile Tigre ($15) second and Spirit Of Boom ($11) another three-quarters of a length away third.

It was Mrs Onassis' seventh win from 12 starts at 1100m.

"She's just getting better as she gets older," Ryan said.

"After she won here in the spring, Gerry said to aim at the Oakleigh Plate."

The Group One Galaxy is the next target.

It's over 1100m.

The victory also gave Kerrin McEvoy a Group One win on a day when he expected to play a major role in the Blue Diamond Stakes only for Guelph to finish out of the placings.

Jason McLachlan was delighted with the performance of Facile Tigre, but must be wondering what it's going to take to win the Oakleigh Plate after the gelding was beaten into third in a close finish last year.

For Ryan, his first Group One win since Melito's Winter Stakes success in 2010 is set to bring about a change.

"I said the next Group One I won I'd give up smoking," he said.