Brazil's Jorge Zarif, favourite in the Finn class, won his opening race at the Sailing World Championships in Aarhus ©Getty Images

An opening day of tricky conditions at the fifth Sailing World Championships the Bay of Aarhus in Denmark - a major test and qualifying opportunity for Tokyo 2020 - put a premium on experience as accomplished Olympic sailors prevailed over the conditions of fluctuating winds.

The men’s 470 class of 65 boats was split into two fleets, and the two opening races for each one were won by the Swedish 2018 European champions, Anton Dahlberg and Frederik Bergström, and the Greek Olympic bronze medallists at Rio 2016, Panagiotis Mantis and Pavlos Kagialis.

Behind the Swedes, Australia’s Mat Belcher and William Ryan - London 2012 Olympic champions and Rio 2016 silver medallists, and winners of the last two world titles - recovered from 14th to finish strongly in third.

The women’s 470 class numbered one fleet of 47 boats which managed two races.

Switzerland’s Linda Fahrni and Maja Siegenthaler, winners of the test event in Aarhus this time last year, dominated the first race from start to finish.

But it was the French who had the best day overall, as Camille Lecointre - the Rio 2016 bronze medallist - and her new crew Aloise Retornaz were a clear second in the first race and managed sixth in second race, where the Swiss finished 13th in a race.

Victory in the second race established Japan’s Ai Kondo Yashida and Miho Yoshioka in second place overnight following their opening 12th place.

Britain’s Olympic gold medallist at Rio 2016, Hannah Mills, and her new crew Eilidh McIntyre, had a tougher day, finishing ninth and 14th to lie eighth overall.

In the Finn class both fleets - 90 sailors from 41 countries split into two fleets of 45 - managed one race each and the first was won by the 25-year-old Brazilian favourite, Jorge Zarif, fourth at Rio 2016, but who has dominated so far this year.

Zarif is the son of the late Jorge Zarif Neto, who finished eighth at Los Angeles 1984. 

Australia's Mat Belcher and William Ryan made a solid start to the defence of their 470 class world title in Aarhus ©Getty Images
Australia's Mat Belcher and William Ryan made a solid start to the defence of their 470 class world title in Aarhus ©Getty Images

Brazil’s most decorated sailors, Torben Grael and Robert Scheidt, here to support another strong Brazilian team, were in the boat park to offer him encouragement.

In the second fleet, Croatia’s Josip Olujic, was more of an outside winner, leading from start to finish.

Max Salminen, who won gold in the Star class at London 2012, and the Finn World Championship last year, is ranked second in the world behind Zarif and finished strongly for third place.

Belcher summed the day up after his 470  race.

 "As a sailor trying to race in those conditions, you’ve got to be a bit lucky and you also have got to just try and be patient," he said.

"We had a great start, tried to consolidate and then found ourselves at the back in 15th or 16th at the top mark.

"But I guess the strength of our partnership is that we just keep chipping away.

"We’re stoked to finish third.

"It’s an awesome, challenging venue and I guess that’s part of being at the Worlds right?

"It’s supposed to be a test."