The Frenchman, the Rio 2016 Olympic bronze medallist who was also third at last year's World Championships in Torbole in Italy, recorded two victories and a second place at Sorrento Sailing Couta Boat Club.

He has four points and an advantage of one over Dutchman Kiran Badloe, the defending world champion.

Badloe is locked in an intriguing battle with compatriot Dorian van Rijsselberghe, the London 2012 and Rio 2016 Olympic gold medallist, for the Dutch Tokyo 2020 spot.

With each country only allowed one windsurfer in this year's Olympic RS:X competitions, many nations are using the event in Australia to decide who gets their spot.

This means a difficult decision for the Dutch between the holders of the sport's two most prestigious prizes, but Badloe took the early bragging rights with a victory and two second places.

Van Rijsselberghe was competing in a different fleet so did not get to test himself directly against Badloe.

He started slowly with an 18th-place finish but also came first and fourth to sit 12th overall with 23 points.

Thomas Goyard is third overall, ending third, sixth and second for a total of 11.

Italy's world number one Mattia Camboni was fourth, fourth and fifth for 13 points, and is fifth overall.

"I'd like to go to the Olympic Games but I am also keen to defend my title at the same time," said Badloe.

"We [Van Rijsselberghe] are still good mates and we haven't got much of a rivalry just yet this week. 

"We are good mates off the water, we live together and share the same car down to the venue together so as mates it's fine but on the water we both want to beat each other."

Dziarnowska was second, fifth and fourth to end day one on top of the women's leaderboard with 11 points.

Britain's Emma Wilson ended second after a victory and two eighth places left her on a score of 17.

Dutchwoman Lilian de Geus was first, third and 18th and tallies 22 points in overall third place.

France's reigning Olympic champion Charline Picon ended day one in seventh with 28 points after finishing sixth, fourth and 18th.

Yunxiu Lu of China is not defending her title due to the coronavirus outbreak, which means the world number one is absent.

"It was a pretty good day for me and I am very happy with my performance, especially the starts which I think is the key to having a successful day today," said Dziarnowska. 

"Every time I went to the Race Committee I was pleased that I had not had a bad start.

"These conditions are my favourite, I could do with a little more wind as I love these planning conditions. 

"The forecast for tomorrow makes me really excited and I jut hope it is race-able – if it's over 30 knots it will be difficult for the Race Committee."

As well as the battles between sailors from the same country, the event is also serving as the Oceania Olympic qualifier.

The highest ranked sailor from either Australia of New Zealand in each fleet will earn a quota spot for Tokyo 2020.

Antonio Cozzolino currently leads in the men's event for New Zealand, in 51st place overall.

His team-mate Veerle ten Have leads the women's race in 28th place.