Defending women's 470 champions Jo Aleh and Polly Powrie have responded to adversity by powering into the lead in Rio.

The Kiwi sailors produced a fourth and a race win in the second day of their class to forge a narrow advantage over Japan's Ai Kondo Yoshida and Miho Yoshioka.

It was close to the perfect response from Aleh and Powrie, who suffered a major setback in the jury room late on Wednesday, when disqualified following a protest following an incident in race one.

Relegated from second to 10th overall, the Kiwis were again prominent in both races on Thursday, finishing 50 seconds clear of the fleet in race four on Guanabara Bay.

Advertisement

Sitting on six points, they lead Japan by two, with another three points back to three boats. That group includes British pair Hannah Mills and Saskia Clark, who fought a terrific duel for gold with Aleh and Powrie four years ago.

The biggest movers on day four of the regatta were busy Nacra 17 pair Jason Saunders and Gemma Jones, who climbed from 13th to fourth.

After finishing outside the top eight in their first two races on Wednesday, Jones and Saunders were seventh, fifth, fourth and second to be on 27 points and 10 points behind co-leaders Australia and Great Britain.

Josh Junior also enjoyed his best day in the Finn class, improving five places to 15th overall courtesy of a fifth and a third.

Junior has four remaining races in which to qualify for the medal race in a class still being dominated by British world champion Giles Scott.

Moving in the other direction was men's 470 crew Paul Snow-Hansen and Dan Willcox, who slumped from third to 11th overall. Poor starts proved costly as they placed 20th and 15th.

It was a reserve day for seventh-placed Laser sailor Sam Meech while two Kiwi combinations will begin their competition on Friday - 49er world champions Peter Burling and Blair Tuke, and 49erFX women Alex Maloney and Molly Meech.