Trainer Gary Portelli has no qualms about sending Dio D'Oro out on a heavy track again after his last-start maiden win at Randwick.

The Warwick Farm trainer will bring the promising colt back to Randwick on Saturday when a similar surface to the ground Dio D'Oro encountered earlier this month is predicted.

Dio D'Oro won over 1000 metres at his fourth start for Portelli and Darby Racing on June 9 and the two-year-old has recovered well from the testing run.

He now steps up to 1200m for the Living Turf Handicap in which the field includes fellow last-start winners King's Trust, Knight Arrow and Godolphin colt Mamaris.

"He certainly hasn't looked at any stage like he's gone backwards," Portelli said.

"The only thing I'm concerned about is when horses put in such a big run first-up, their second-up run can be disappointing."

With Randwick already in the heavy range and more rain forecast on Thursday, Portelli is relatively at ease.

"I believe if they've been on a heavy and you bring them back to a good their next start, the heavy takes the speed out of their legs sometimes," he said.

"They're just not quite as sharp when they get back on top of the ground after a heavy track run.

"He swam through it last start and he's not going to need his speed. He'll need his stamina more than a turn of foot and he's rock hard fit. He shouldn't be flat."

Dio D'Oro opened his career in January by finishing runner-up to eventual Golden Slipper winner Estijaab at Randwick and despite his recent victory, Portelli will not set any lofty long-term goals.

"That next level of horses is pretty tough. We'll make hay while the sun shines. If he ends up in that grade, that'll be great," he said.

Rachel King again takes the ride as she attempts to increase her lead in the Sydney apprentices' premiership.