John Sargent believes Quintessential is close to recapturing the form which saw her win last year's Queensland Oaks.
The mare will be reunited with her Oaks-winning jockey Damian Browne in Saturday's Chairman's Handicap (2100m) at Eagle Farm.
"She's well in herself and coming to her peak now," Sargent said.
"In the spring she didn't mature after some hard runs in the winter so we backed off and aimed her at this carnival."
Quintessential has had a gradual build-up in four races in New Zealand and pleased Sargent with her latest effort when third to Pimms Time in the Group Two Travis Stakes (2000m) at Te Rapa on April 27.
"She went back at the start then she was the first one to make a move and had to come right around them," Sargent said.
"She did a lot of work that day but she still finished it off well."
The mare has drawn poorly in barrier 16 but Sargent will entrust Browne to come up with a suitable riding plan.
"Whether she goes forward or back from that gate is a bit tricky but Damian knows her well so I'll leave it up to him how he wants to ride her," he said.
"He's a lovely cool, calm rider and I'm sure he'll make the correct call."
Sargent abandoned Quissential's spring campaign after only three starts when she failed to replicate her winter carnival form.
"It knocked her a bit backing up in the (Queensland) Derby from winning the Oaks on a very heavy track and it's taken her awhile to get over that but she's coming back to her best form now," he said.
The four-year-old's racing future beyond her Queensland campaign will be decided by owner Greg Tomlinson, who bought into multiple Group One winner All Too Hard, the half-brother to Black Caviar.
Sargent will decide if Quintessential's stablemate Cathay Lady will campaign in Brisbane during the winter after she has her next in the Scone Cup (1600m) next Friday.