In front of the Duke and Duchess of Sussex the Australian team onboard the Elliot 7 put in a stellar performance against rising winds to take out the gold medal.

Fellow Aussie teammates Peter Arbuckle took out silver and Davin Bretherton bronze in the Hansa division.

Out on the water, Simone Cooper was cheering her partner Paul Langley as he finished in first place.

"I was balling when they crossed the line, I just grabbed Rob's wife and we hugged for ages," Simone told AAP.

"We just knew how much they'd gone through."

Simone said Paul's spirits had been high after each training session in preparation for the games. When it came to crunch time the team's camaraderie certainly helped get them over the line.

"There were times in that race today where the wind just went out of the sail and they had to work damn hard to make it happen and then all of a sudden off they go," Simone said.

"And hallelujah we got the gold."

After powering from third place up to first, team captain Rob Saunders said he felt "elated" to secure the win.

"The final race we had to really fight for the wind, it was really shifty," Rob told AAP.

"We couldn't believe we won but it felt fantastic."

It's the first time sailing has been part of the Invictus Games as an open event for all competitors.

Hundreds gathered at Mrs Macquarie's Chair while others lined the Opera House stairs to cheer on their nation.

Locals have also volunteered their time and boats to take friends and family of the competitors out on the harbour for a prime viewing spot of the races.

Australian flag bearer for the Sydney Invictus Games opening ceremony Jeff Wright was among the crowds cheering on Arbuckle and Bretherton.

Wright, who will be competing later on in the wheelchair rugby and basketball, said he was proud of his colleagues who had taken up a new sport to aid their road to recovery.

"They're new to it. This is their first crack at sailing," he told AAP.

"They've really picked it up quickly and are quietly confident they have enough skill to trouble the rest so I'm expecting big things."

The pregnant Duchess of Sussex was out on the water with Prince Harry to watch the Invictus Games sailing after taking a break earlier in the day.

Australian Associated Press