There was no winning return for Tom Melbourne but trainer Chris Waller believes there is an upside to the latest in a series of near misses.

After watching Comin' Through prevail in a tight finish with his stablemate in the Group Two Ajax Stakes (1500m) at Rosehill, Waller said both horses would head to next month's Group One Doncaster Mile at Randwick.

While Sydney's premier trainer considered four-year-old Comin' Through a genuine lightweight chance for the $3 million Doncaster at Randwick on April 7, he would not discount Tom Melbourne's hopes of engineering an upset.

"He saved himself carrying extra weight today. He might win the Doncaster and we'll say he's a hero, he knew what was around the corner," Waller said.

Tom Melbourne looked like winning for the first time in 20 starts since the 2016 Albury Cup, but the $3.50 favourite had to settle for the ninth second placing of his career.

"I thought Tom had his measure but to Comin' Through's credit he fought very bravely," Waller said.

Comin' Through ($5) prevailed by a long head while Radipole ($8) was a half-head third.

Waller was upbeat about Comin' Through being competitive in the Doncaster Mile with Saturday's victory seeing him shorten from $26 to $15.

"He's down right at the weights, he was placed in the Randwick Guineas as a three-year-old, he's never been far away in some of the best races in town," he said.

"I'd be pretty bullish about his chances."

Comin' Through was gelded before this preparation and a second-up win following a third in the Group Two Apollo Stakes has vindicated the decision.

"It was a hard decision, especially for (owner) Sir Owen Glenn because he's a passionate breeder," Waller said.