Matt Wearn knew he had the gold medal sewn up for a couple of days.(Getty Images: Phil Walter)

Matt Wearn has made his win in the men's laser event official after finishing second in the final race to give Australia a record fourth gold medal on day 9 at the Tokyo Olympics.

Wearn had already wrapped up his victory in Friday's penultimate round but he needed to at least make a genuine effort to finish Sunday's medal race to confirm he had won gold on Fujisawa City's Enoshima Yachting Harbour.

The West Australian placed second to France's Jean Baptiste Bernaz in the medal race.

His triumph contributed to Australia's best ever single-day performance at an Olympics following the three gold medals won across swimming and BMX earlier on day 9.

"The goal was just to go out and have a clean start and be able to race from there," Wearn said.

"To be able to do that and just enjoy the race was awesome."

"It was a great experience — nice wind, good waves. When the wind's like this the sport is just amazing and you really start to enjoy it."

Wearn said winning the gold medal was built on the family support he had received.

"Mum and dad have sacrificed so much to get me to where I am today," he told Channel Seven.

"All that time … sitting out the front of the gym in the car, I can't thank mum enough. My brother and sister, extended family as well.

This is as much their gold medal as it is mine."

Croatia's Tonci Stipanovic took the silver medal, with Hermann Tomasgaard of Norway picking up the bronze.

This is the third straight Olympics Australia's sailing team has won the men's laser event, following the victories recorded by Tom Slingsby (20212) and Tom Burton (2016).

Wearn hit a sweet spot during the 10 opening series races that decided the 10 boats that would contest the medal race, which was worth double points.

He recorded two wins and three second place finishes to go into the medal race with an unassailable lead.

The 25-year-old topped the overall standings after a superb Olympic campaign on 53 points, with Stipanovic a distant second on 82 and Tomasgaard three points further back.

Wearn, who made his Olympic debut in Tokyo, is coached by Michael Blackburn, who claimed the bronze medal in the men's laser at the 2000 Olympics.

 Blackburn also coached Slingsby and Burton to their Olympic victories.

Wearn was a talented Australian rules player as a junior but chose to stick with sailing as his sport.

Source: www.abc.net.au