Training a star colt comes with its share of pressure and Richard Litt admits he was feeling it before Castelvecchio's return to the Group One winner's list in the Rosehill Guineas

Runner-up in the Cox Plate last spring, the three-year-old had finished unplaced at his first two campaign runs and the jury was out on how well he had returned.

But like he did in the spring, Castelvecchio came into his own once stepped up to 2000-metres in Saturday's Rosehill Guineas, reasserting his place as one of the country's brightest talents.

The win was a pressure release for Litt, who had been adamant the horse was going as well as ever and Castelvecchio proved him right at Rosehill.

"For me to reproduce another Group One winner, it's huge for my training career and very special," Litt said.

"There was a little bit of pressure. I always says pressure is for tyres but today we felt it and we're lucky we've got a great horse.

"He showed his true colours and we're so proud of him."

Craig Williams rode Castelvecchio in the Cox Plate and was reunited with him for the first time since then.

From a good draw, he settled the colt behind the pace, which changed a couple of times as horses trapped wide made midrace moves.

Williams bided his time, hooked Castelvecchio ($7) into clear space on straightening and he outstayed a game Prince Fawaz ($41) to win by a half length.

Reloaded ($10) was another 2-1/2 lengths away with Randwick Guineas winner Shadow Hero ($3.20 fav) finishing hard from well back for fourth.

Litt said he did not give Williams instructions, rather the Melbourne Cup-winning jockey provided a run down of his game plan.

"I couldn't get a word in before I legged him on, he knew exactly what was happening," Litt said.

Castelvecchio holds nominations for the Australian Derby (2400m) and Queen Elizabeth Stakes (2000m), run one week apart in April, and Litt flagged the possibility he could contest both.

"We will let his connections sit down over the next week and make that decision, today he looked like he was running away from them and he'd eat up a Derby," Litt said.

"But obviously we've got the Queen Elizabeth the week after that and there's wonderful prize money so we've got plenty of thinking to do."

Josh Parr said Shadow Hero was shuffled too far back and his midfield draw cost him.

"We ended up four lengths further back than we would have liked in a stop-start affair. The gate was probably the difference," Parr said.

Anthony Cummings was delighted to see Prince Fawaz return to his best but was rueing a missed opportunity.

"I thought he was home for a bit and it was a Group One," Cummings said.

"He took nice steps off his run last time and he's getting back to his right form."

The Guineas had a sombre footnote with New Zealander Scorpz breaking down after the post.