Perast and Summer Passage settled first and second in Sunday's Group III Caulfield Guineas Prelude (1400m) at Caulfield and the order only changed once.
Having raced on the outside of Summer Passage to the home turn, Perast ($11) gradually asserted his superiority for Damian Lane in the home straight to defeat Summer Passage ($17) by a length with Kementari (3.80), third all the way, a head off in third place.
The previously undefeated Royal Symphony started an easing $2.40 favourite and made late ground to finish fourth, beaten 3 1/4-lengths.
The Paul Perry-trained Perast had finished seventh last time out in the Golden Rose at Rosehill and Perry said the son of Snitzel had fitness on his side.
"He's come down here very solid in condition and he's been running in Group One races at home," Perry said.
"He's got plenty of heart and he did well to grind that out."
Perast will run next in the Caulfield Guineas and Perry said the extra distance will suit.
"The mile will suit him much better than today and I even think he can get out over further," Perry said.
"The way he's bred, out of a Zabeel mare, I can only see him improving. He relaxes so well in his races now it all helps."
Tony McEvoy was gracious in defeat with Royal Symphony.
"Disappointed on face value but I think when we dissect the race it was still a very good performance," McEvoy said.
"Nothing took him into the race and he was a long way off them, it was his first time at Caulfield and Dwayne (Dunn) is suggesting adding some winkers just to keep the colt focussed.
"Out to the mile will be better again and when we get over the disappointment of defeat today we'll still see a lot of merit in the performance."
It's that man again, @lanedamian. Perast powers home to score in the Caulfield Guineas Prelude. pic.twitter.com/doHK3vqXot
— Racing.com (@Racing) October 1, 2017