Blake Shinn says the sky's the limit for Summer Passage, who provided the leading Sydney jockey with a memorable victory at Ellerslie.

His aggressive ride aboard the Lance O'Sullivan and Andrew Scott-trained and Hong Kong-owned colt paved the way for their dashing victory in Thursday's Gr.1 Sistema Stakes.

"He's an exceptional two-year-old and it's a big thrill to get my first Group One winner overseas," Shinn said.

"I'm delighted to have got the opportunity to ride such an exciting horse."

It was his fellow Australian jockey Zac Purton who had originally been booked for Summer Passage, but the postponement of the meeting from Saturday resulted in the Hong Kong-based rider's unavailability and Shinn received the call.

"I didn't expect to be here today and I feel for Zac who has missed out due to unfortunate circumstances," Shinn said.

He bounced Summer Passage out from the widest gate to sit outside the leader and, when asked, the son of Snitzel showed sharp acceleration in the straight to beat Star Treasure and Gold Fever.

"I took the initiative from the wide draw to go forward and kept him in a comfortable rhythm," Shinn said.

"He showed a great turn of foot 300 out to put the race to bed."

A crack at the $A1 million ATC Sires' Produce Stakes at Randwick on April 1 will now be a hot topic of discussion for the Summer Passage team.

"We'll talk to Blake and the owners and then make a decision, it's certainly on the radar," O'Sullivan said.

"This has been a tremendous thrill, it's a great result. The first time we ran him up at speed he showed a lot of natural ability so it's pretty special for Andrew and I and the team at home."

Summer Passage is owned by Hermitage Thoroughbreds, who also raced the Gr.1 Livamol Classic winner Willie Cazals out of O'Sullivan and Scott's Wexford Stables.