Star colt Pierro has kept his unbeaten Sydney record intact - but only just.

The odds-on favourite for the Group Two Hobartville Stakes at Rosehill, Pierro had to dig deep to hold off Rebel Dane who stamped himself as a genuine contender for the big autumn races with his short-head second.

Nash Rawiller admitted to some anxious moments aboard Pierro who was racing for the first time this campaign and the first time without blinkers.

"He got very tired," Rawiller said.

"Maybe I should have waited another 100 (metres) before I let him go. He was running on empty at the 50 and I thought the other horse would get him but he dug deep."

Trainer Gai Waterhouse said Pierro was there to be beaten, but showed his class.

"He was at his most vulnerable today first-up without the blinkers," she said.

"You don't have to win by much."

Even though Waterhouse predicted much improvement from Pierro's outing, Rebel Dane's trainer Gary Portelli was just as bullish.

"My horse came back at Pierro and has done a great job," he said.

"Look out the Randwick Guineas. Here we come."

Rebel Dane's jockey Jason Collett said his opponent had more than a length on him at the 200m and he thought his colt could get him near the line.

"He was so good," he said.

"But this is Pierro."

Pierro is unlikely to head to the Guineas (1600m) in two weeks but it is a target for his stablemate Proisir, who finished 2-3/4 lengths from Rebel Dane.

Waterhouse said she had not locked in a program for Pierro with the weight-for-age George Ryder Stakes and the Doncaster Mile among the options.

Those could also be options for All Too Hard who was withdrawn from Saturday's Australian Guineas with a virus.

All Too Hard inflicted defeat on Pierro in the Caulfield Guineas in the spring and again finished in front of him in the Cox Plate.

But Pierro's nine starts in Sydney have all been winning ones while All Too Hard's Cox Plate second is the only time he has been beaten in Melbourne.

His record includes the 2012 juvenile triple crown of the Golden Slipper, Sires' Produce and Champagne Stakes.