Olympic equestrian gold medallist Stuart Tinney produced show jumping perfection on Sunday to claim an unexpected Australian International Three Day Event title.

Tinney, riding Panamera, captured his second Australian International title in three years with a faultless performance at Adelaide's east parklands.

The Sydney 2000 Olympic teams gold medallist recorded no jump or time faults in the defining show jumping phase to overhaul the leaders.

Tinney finished on 51.30 points, eclipsing Sonja Johnson, on Parkiarrup Illicit Liaison, with 53.80 points and emerging rider Emma Mason, on F1 Pharinelli, was third on 55.20 points.

Overnight leader Shane Rose, on Taurus, endured a horror show jumping stage with 16 jump faults - only one rider jump faulted more times - and slid to fifth place.

Rose's slip-ups allowed Tinney, aiming to ride for Australia at his fourth Olympics in London next year, to rise from a fourth position overnight to take overall honours.

"She (Panamera) is a very good jumper and I knew if I rode her well enough then I had a good chance to jump a clear round, but I didn't expect to win," said Tinney.

The Adelaide event was only one of six on the international equestrian calendar given FEI Classic status - the highest level competition for eventing in the world.

But Tinney was undecided on his immediate future in the classic series.

"I haven't really thought about that just yet, I didn't know I was going to win," he said.

"The main focus is the Olympic Games."

The Adelaide event was crucial preparation for Australian based riders in their bids to win selection for the London Games, with more than 10 combinations competing in the frame for the Olympics.

AAP