2022 Moonee Valley Vase Replay
O'Sullivan was confident Berkeley Square could compete in the Caulfield Guineas last start, and he did that, finishing fourth.
He carried that good form into Saturday.
“It was a good race, wasn't it? It was a big challenge up the straight there,” O'Sullivan told Racing.com.
“I was really pleased to get the result for the owners.
“I've always said 2000m would be his limit. It was a really exciting race and he was really tough through the line.”
“It'll be interesting how much this race takes out of him. If the run affected him it'd be the only reason I wouldn't go,” he said.
Williams said O'Sullivan did an outstanding job preparing his middle-distance stable star for Saturday's effort.
“Credit to Dan O'Sullivan, he's done a great job,” he said.
“He's really managing and most importantly developing this horse.
“And it'll be exciting to see where Dan and the owners decide to go with him in the near-future.”