The world number 57 triumphed in torrential rain in the Brazilian city, winning the event which is also serving as the test competition for August's Olympic Games.

Cesarini was 30th quickest after the swimming, but she built on her winning performance in yesterday's fencing by beating Russia's Donata Rimsaite in the decisive bout of the bonus fencing round at Deodoro Park.

She was then sixth after the riding which allowed her to begin the combined run/shoot in podium contention.

The Italian moved convincingly past China's Qian Chen and Brazil's home favourite Yane Marques, who was first to start the combined event after a strong consistent performance.

She only began eight seconds in front of Cesarini, however, and was never in contention for victory.

A strong challenge by Germany's Lena Schoeneborn, who won the opening World Cup of the season in Cairo, saw her advance from ninth to the silver medal.

Rimsaite won bronze to complete the podium.

"It's a dream, and I can't believe it," said Cesarini. 

"I had a pain in my stomach throughout the qualification, and I was afraid I would not be able to run, but I had a lot of help from the Brazilian physiotherapist."

UIPM President Dr Klaus Schormann said the test event had been greeted positively.

"It was an exciting day but it finished with an awful thunderstorm, which was a pity for the athletes," he said.

"They gave their best all day on what will be the facilities for the Olympic Games.

"We can say that this was a successful Olympic Test Event, with the best athletes again at the front."

The men's individual final will be held tomorrow, before the mixed relay on Monday (March 14).