The duo had been forced to settle for the silver medal at the 2015 edition of the event and began the day two points adrift of the race leaders, Paul Snow-Hansen and Daniel Willcox of New Zealand.

They looked like falling further behind after finishing as runners-up to the Kiwis in the opening race of the day, which eventually took place after competition was delayed due to a lack of wind at the Argentinian venue.

Fantela and Marenic responded impressively by winning the second race to overtake their rivals, who had only been able to secure a fourth place finish.

The Croatians have now moved onto 42 points for the regatta and will look to protect their 13 point advantage over Snow-Hansen and Willcox in tomorrow’s medal race.

“We had a great day in a difficult spot like any other day, and I am really pleased how Igor and I sailed today, practically and technically as well,” said Fantela.

“I am just feeling happy and relaxed right now.

“It was another long day and we are just looking forward to tomorrow, to stay focused, stay calm and that is the plan.”

Mathew Belcher’s run of successes at the Championships looks likely to come to an end, although the six-time gold medallist has the outside chance of gold, as he lies 15 points behind the race leaders with William Ryan.

France’s Camille Lecointre and Helene Defrance were able to extend their lead in the women’s event, despite fifth and 14th place finishes.

They had begun the day three points ahead of Xiaoli Wang and Lizhu Huang, but the Chinese pairing were only able to secure 10th and 18th place results and now lie fourth.

Austria’s Lara Vadlau and Jolanta Ogar are now the closest challengers to Lecointre and Defrance, after they ended as runners-up in the opening race of the day, before backing up that result with a fifth.

The duo are six points off the lead, with New Zealand’s Jo Aleh and Polly Powrie a further point adrift in third.