The world champion went into Saturday's racing as the overall leader and managed a victory and a third place.
With the lowest score winning, Scott is on 22 points - 16 clear of Slovenia's Vasilij Zbogar with three races left.
Scott, 29, is a four-time world champion bidding to follow in the footsteps of compatriot and four-time Olympic champion Sir Ben Ainslie.
"It's looking good going into the next two races but there's still a lot to play for," said Scott.
"Obviously having that points margin is a big confidence booster but I think the thing for me to be focusing on is that it isn't over.
"You can't get complacent. You have to attack days like I've done today so nothing really changes. But clearly having that margin is a good place for me."
Nick Thompson's medal hopes in the Laser category took a blow, as he finished 22nd in the 10th race, dropping to sixth.
Thompson, 30, was second after six races, but is 10 points outside the top three going into the medal race, which is worth double points.
Alison Young kept alive her hopes in the Laser Radial, winning the penultimate race to be eighth going into the medal race.
Ben Saxton and Nicola Groves dropped to third in the Nacra 17 mixed category, after they finished outside the top 10 in three of their four races on Saturday.
Charlotte Dobson and Sophie Ainsworth are sixth in the women's 49er class while in the men's equivalent Dylan Fletcher and Alain Sign are 12th.
Dylan Fletcher and Alain Sign have risen from 14th to 12th in the 49er fleet, but face a tough ask to finish in the medal hunt.

Pritchard, a former England Under-21 international, has made two senior appearances for Spurs.
He has scored a total of 20 goals in 100 matches on loan at Peterborough, Swindon, Brentford and West Brom.
The 23-year-old would become Championship club Norwich's third summer signing, after keeper Michael McGovern and winger Sergi Canos.
Find all the latest football transfers on our dedicated page.

A fight which started on Monday evening at a food distribution centre was initially broken up by police but later continued into the night.
Hundreds of migrants live in informal camps in the Calais port, trying to cross into Britain illegally.
French police have spent months trying to break up the camps, but the migrants say they have nowhere else to go.
The latest fight between Sudanese and Eritrean migrants was broken up for the second time once riot police were deployed.
A similar incident on Sunday left about 13 people injured.
In May authorities attempted to evacuate the migrants from camps built near the port following court rulings, but many have simply moved to different areas in the city.
Britain's Giles Scott enjoyed another dominant day in sailing's Finn class to close in on Olympic gold.
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Norwich City are in talks to sign Tottenham Hotspur midfielder Alex Pritchard, reports BBC Radio Norfolk.
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Clashes between African migrants in the French port city of Calais have left more than 50 people injured.