Emma Moffatt successfully stepped up to long-course triathlon on Sunday before a New Zealander stepped in to claim her short-course title.
Moffatt, the Beijing Olympic bronze medallist, went close to pulling off a major upset in her debut over the half-Ironman distance at Geelong.
She pushed pre-race favourite Melissa Hauschildt before running out of steam in the last few kilometres of the run and finishing second in the Urban Long Course.
Later in the day, emerging New Zealand triathlete Sophie Corbridge won the Oceania Cup sprint-distance race - the same event Moffatt won a year ago.
Sydney's Christian Kemp claimed his second major win so far this year when he held off former Hawaiian Ironman top-10 finisher Luke Bell to take out the elite men's long-course race.
While Moffatt remains focused on the 1.5km swim, 50km cycle and 10km Olympic format and wants to compete at the 2016 Rio Games, she stepped up to the 1.9/90/21.1 long-course combination to open her season.
After a superb swim, Moffatt held the lead until late in the bike, when Hauschildt took over.
Hauschildt started the run with a 90-second lead, but Moffatt only trailed by 15m in the last few kilometres before fading.
Hauschildt, the former long-course world champion, won in four hours 11 minutes and 20 seconds.
Moffatt finished a minute and 14 seconds behind her and Anna Cleaver was third in 4:24:03.
"I really enjoyed it until about 15km into the run and then I questioned what I was doing and I couldn't wait until my next Olympic distance," Moffatt said.
"I thought everything was going to fall a little bit apart but it was a good experience and I hope that someday I can do another one."
Moffatt was one of three prominent Olympians to step up to long-course racing at Geelong.
Bell pushed Kemp throughout the run and there was only 32 seconds between them at the finish.
Kemp won in 3:47:21 and James Hodge was third in 3:49:48.
The sprint-distance triathlon featured a 750m swim, 20km cycle and 5km run.
Corbridge and Frenchman Gregory Rouault won, while Peter Kerr's third place and newcomer Grace Musgrove (second) claimed the Australian sprint-distance titles.
The two triathlons were part of the Geelong Multisport Festival, which also featured wins by Scott McPherson and Laura Widdall in the Olympic-distance race.