Olmo conquered the 750 metre ocean swim, 20 kilometre technical bike course and 5km run in 1hr 3min 27sec.

Switzerland's Annen Jolanda was just behind her in 1:03:28, while Jaz Hedgeland of Australia was third in 1:03:36.

“I don’t believe it, I really don’t believe it," Olmo said.

"I was expecting to podium but not for the win."

Australia's Luke Willian won gold in the men's competition, triumphing in 56:05. 

“I had a good swim today, we rode really well and made sure I was at the front into transition," he said.

"We know it’s a technical course so it was really important to get out in front. 

"I started out in front and kept going and didn’t look back."

Justus Nieschlag of Germany and New Zealand's Sam Ward finished in 56:11, with Nieschlag awarded second place and Ward third.

Spanish Olympian Javier Gomez made his return to short-distance racing in a bid to compete at the Tokyo 2020 Olympic Games.

He finished fifth in 56:18.