Damien Seguin of France and Heiko Kroger of Germany jointly lead the 38-boat 2.4 Norlin OD fleet at the Para World Sailing Championship in Sheboygan in the United States.
Four fleets got underway on Lake Michigan in cooling temperatures, and Seguin enjoyed an early flourish as he won his first race.
"I was second at the first upwind but then I took the lead and got a big advantage,” he said.
"It was a good race for me.”
The second race was different.
"It was amazing,” he said.
“Five boats were leading and after the downwind mark, one group chose the left and the others chose the right.
“There was no wind but it filled in on the right where I was so it was crazy.
"Anyone could have won."
Kroger did win, to tie with Seguin in the overall standings, with Dee Smith of the United States four points off the leaders.
Seguin has been in fine form in 2018 in the 2.4 Norlin OD, winning the World Cup in Hyéres, France and the European Para Sailing Championship but recently, he’s been sailing a boat 52 feet more than the 2.4.
The RS venture connect made its debut in the Championships and Alexandra Rickham and Hannah Stodel of Britain had the best of the day.
Rickham, a London 2012 bronze medallist, and Stodel, a multiple world champion in the Sonar, are two of the most experienced competitors in the fleet and it showed as they won four of six races in Group A.
"All in all it seemed to go alright,” said Rickham.
"I can’t be unhappy about today.
"It was quite varied and the wind was really up and down.
"The sea state was all over the shop as well.
"There was quite a bit of swell at the beginning but that flattened off, so lots of big wind shifts in the second half.
"It was quite difficult and a lot of us haven’t sailed the boat that much so it was quite a big learning curve.”
Gianluca Raggi and Davide di Maria of Italy picked up three victories in Group B.
The winner of each group will automatically advance to the winner-take-all race on Saturday (September 22).