British sailor Ben Ainslie hit back with two first places on day two of the Finn class after being disqualified from Saturday's race two.
Ainslie clawed his way back to eighth overall in strong, gusty winds on the Saronic Gulf after plummeting to 19th.
Nick Rogers and Joe Glanfield stayed top of the 470 standings after day two with a ninth and fourth place.
Shirley Robertson's Yngling crew also lead after four races, while Laser star Paul Goodison was 13th and third.
The British team are investigating whether Greek television pictures of Saturday's second Finn race may provide Ainslie with evidence to support an appeal against his disqualification for infringing the right-of-way rules.
"We'll look at it further and take some advice from rules experts and if we decide, we'll lodge an appeal in the morning," British team boss Stephen Park told BBC Sport.
"As far as Ben's concerned he's disqualified, and is just concentrating on the rest of the regatta. Anything we get out of this will be a bonus."
The biggest threat to Ainslie's chances, Mateusz Kusznierewicz of Poland, was sixth and fourth on Sunday but still leads overall.
Ainslie won gold in the Laser in Sydney and his successor in the class Goodison ended his first day on seventh overall.
Glanfield (left) and Rogers are going for gold in the 470 class
Rogers and Glanfield led the standings after a second and third place on day one but a ninth on Sunday saw them cede the top spot.
But they snatched it back after race four to lead Americans Paul Foerster and Kevin Burnham by eight points overall.
"Having sailed in these conditions we knew there was a chance to get back at the leaders if we didn't lose our heads," said Glanfield.
Sydney Europe class gold medallist Robertson, with new crew Sarah Ayton and Sarah Webb, won both races in the Yngling keelboat on day two to climb to top spot in the overall standings.
In the men's Mistral windsurfer class, Nick Dempsey placed 19th and 12th in his first two races for 17th overall, while Natasha Sturges was 16th and 13th in the women's event
Team-mate Laura Baldwin came 21st and 15th in the first two races in the Europe class and Christina Bassadone and Katherine Hopson placed 14th and fourth on day two in the women's 470 for ninth place overall.
In all of the classes except the 49er, competitors sail 11 races with the best 10 scores, based on finishing position, to count.
The men's double-handed 49er crews sail 16 races with two discards.