Trainer Danny O'Brien declared "the sky's the limit" for impressive colt Star Witness after he posted his second Group One win in the Coolmore Stud Stakes at Flemington.The winner of the Blue Diamond Stakes last autumn, the son of Starcraft showed he was ready for a showdown with sprint sensations Black Caviar and Hay List over the same course in next Saturday's Group One Patinack Farm Classic with an easy two-length win over Curtana and Shrapnel."We have picked our targets for him this spring a

Trainer Danny O'Brien declared "the sky's the limit" for impressive colt Star Witness after he posted his second Group One win in the Coolmore Stud Stakes at Flemington.

The winner of the Blue Diamond Stakes last autumn, the son of Starcraft showed he was ready for a showdown with sprint sensations Black Caviar and Hay List over the same course in next Saturday's Group One Patinack Farm Classic with an easy two-length win over Curtana and Shrapnel.

"We have picked our targets for him this spring and it is pretty important that you get it right," O'Brien said.

"We were patient; we left the (Caulfield) Guineas alone and waited for this race so there was a lot riding on today.

"To produce him and have him produce today is very satisfying."

James Winks, who joined O'Brien as his stable rider this spring, said it was a dream to ride a horse like Star Witness.

He said the three-year-old was always travelling and had the field covered a long way from home.

As steady rain fell, Pressday blew the start when he reared up and lost several lengths and Solar Charged compounded after leading while Winks plotted his attack just off the speed.

"He just travelled so good," Winks said.

"He is a totally different horse down the straight. He finds a rhythm, he relaxes and I actually had to grab hold of him again (at the 300m), he was just going to get there way too early.

"When I pushed the button he put it beyond doubt."

O'Brien said not even the rain dented his confidence that Star Witness would win on Saturday.

"If you have got a topline horse like him you have got to produce rain, hail or shine," O'Brien said.

He said the colt's spring program was geared towards the Coolmore Stud-Patinack Farm double.

While conceding next week's mission was a big challenge, O'Brien is not afraid to test Star Witness against the best.

"Obviously we are up against Hay List and Black Caviar but this is a pretty special colt," O'Brien said.

"He's only had seven starts now and he's won two Group Ones.

"The sky is the limit.

"Even though he won a Blue Diamond (at Caulfield) he's a much better horse down the straight.

"There are a few options for the straight course, next Saturday and in the autumn and possibly over to the UK in June next year."