The on-again off-again Queensland Derby mission is back in the frame for Rodrico who has shown his tenacity with a hard-fought win at Randwick.

After two wins in April, the Chris Waller-trained gelding lost his position in the pecking order for Brisbane when he ran fourth to stablemate Encosta Line at Randwick on May 7.

He made his way back up the list on Saturday when he claimed Colonel Custer by a nose to win the Evans & Partners Handicap (2000m).

"After he got beaten last time, the Derby was in question but I'd say it's back now," Waller's racing manager Charlie Duckworth said.

"It was a very strong win."

Rodrico's jockey Glyn Schofield said the race did not pan out how he had planned.

"It was not the plan to go to the fence but I had to go there in the end," he said.

"It was a tough effort."

Rodrico's stablemate Pursuit Of Honour finished a neck behind the runner-up and could also head to the Derby if he sneaks into the field.

"He may not have enough prize money," Duckworth said.

Waller's team will be enhanced by Encosta Line who missed a scheduled start in Saturday's Grand Prix Stakes at Doomben with a temperature.

"He's fine now but Chris didn't want to travel him on the day the temperature spiked," Duckworth said.

"He has time to recover."

The Queensland Derby (2400m) at Eagle Farm on June 11 is the final Classic of the season.