The 22 year old had a six penalty buffer leading into Sunday's showjumping decider but the advantage wasn't required with Manson and her horse Legal Star producing one of three clear rounds among the field to finish on a score of 64.60.

Olympic silver medallist Megan Jones and her horse Kirby Park Allofasudden finished the event in second place on a score of 70.70.

Jones gave herself every chance of winning when she also produced a clear round which put the pressure on Manson.

At last year's event Manson and Legal Star knocked three show jumping poles (equivalent to 12 penalties), something that was weighing on Manson's mind earlier in the day.

"I tried not to think about it. I was reasonably confident because he felt really good in the warm up and he was jumping well.

"It was a little bit daunting at the start, but once I got going it all just fell into place. It seemed to come off well and he jumped well so I'm happy.

"(Megan's round) definitely put the pressure on."

West Australian Manson said her move to the east coast had paid dividends.

"It means so much. I have been away from home for a year now training and competing, so to be able to do this after the year away from home is great."

For Beijing 2008 Olympian Jones it is the third time she has finished the runner-up.

"I am a bit disappointed as this is the third time I have placed second at this event but Jess did such a great job.

"I love this event so much, I had four horses here. The crowd is great and we don't get that at any other event in Australia so it is really special event for us."

New South Wales rider Soigne Jackson and Gold moved from 8th position following the dressage to finish in third after incurring eight jumping penalties. Their final score was 95.90.

Victorian Katja Weimann and her horse BP Cosmopolitan were the producers of the third clear round which saw them finish in fourth.