Briton Ben Ainslie kept his cool in choppy seas to claim his third successive Olympic gold after retaining his Finn title on Sunday.
The 31-year-old, needing to finish no worse than six boats behind Zach Railey in the medal race to take gold, coasted to victory while the American was sixth.
Railey won silver and Frenchman Guillaume Florent grabbed bronze.
Ainslie won a silver medal as a teenager on his Games debut in the Laser class in 1996. He won Laser gold four years later in Sydney and gold again in Athens in 2004 after switching to the heavier Finn dinghy.
Ainslie's triumph capped a memorable first medal day in the regatta for Britain after the Yngling trio of Sarah Ayton, Sarah Webb and Pippa Wilson won gold earlier on Sunday.