Heiko Kroger of Germany stormed into the overall lead in the 2.4 Norlin class with two race victories at the Para World Sailing Championships in Kiel.
The German sailor delighted the home crowd with an assured performance on the penultimate day of racing.
Kroger, who finished third in the other race to take place today, is in pole position on the leaderboard with 20 points, one in front of Rio 2016 Paralympic Games silver medallist Matthew Bugg of Australia.
Paralympic champion Damien Seguin of France is a point further adrift in third place.
Bugg ensured he kept in contention for the gold medal, which will be decided during the last day of action tomorrow, by winning the other race.
"It's been a really good standard on the water," he said.
"It was a good day with really good wind.
"I really enjoy heavy air sailing and I'm happy I've moved up."
It proved to be a disappointing day for Seguin, who lost his place at the summit of the leaderboard after recording results of second, sixth and fifth.
Two races are due to be held in the 2.4 Norlin class tomorrow.
In the men's Hansa 303, Rio 2016 Paralympian Piotr Cichocki swept all three races held today and now has a two point advantage over nearest challenger Christopher Symonds of Australia.
The Polish competitor was in fine form as he came from behind to defeat his Australian rival on all three occasions.
Cichoki has six points, with Symonds hot on his heels with eight.
Jens Kroker of Germany occupies the third and final podium position as he is is six further behind on 14.
Spain's Violeta del Reino is in firm control in the women's Hansa 303, picking up two second place finishes and a discarded fifth.
The Spaniard has a six-point lead over Singapore's Qian Yin Yap, who won the third race, with Ana Paula Goncalves closely behind in third.
The event in Kiel concludes with the final set of races tomorrow.