Tom Burton won Australia's seventh gold medal of the Rio Olympics with victory in the men's laser.
The 26-year-old, second going into the final race, finished on 73 points ahead of Croatia's Tonci Stipanovic.
Bronze went to Sam Meech of New Zealand, while Great Britain's Nick Thompson, the 2015 and 2016 world champion, was sixth.
The men's race was due to take place on Monday but was cancelled by a lack of wind.
Brazil's Robert Scheidt was trying to become the first sailor to win a medal in six different Games. He finished fourth overall.
Subscribe to the BBC Sport newsletter to get our pick of news, features and video sent to your inbox.