Day stormed the field in Sunday's race of the 2021 series at Kingscliff, winning by 30 seconds to back up victories on Friday and Saturday and put him in pole position to claim a third championship at the midway point of the season.

The 30-year-old's results are all the more impressive given a year ago he had to sit out the series after breaking both wrists during a promotional shoot in late 2019.

After having multiple screws and metal plates inserted surgically in both arms, Day faced the real prospect of his surf lifesaving career being over.

It was a struggle that Day admits took its toll on him mentally.

"It's probably pretty easy to look back on now and and sort of be like, 'oh it wasn't that bad' but I know ... I was in obviously a really bad way over that summer period when the Ironman series was on," Day told AAP.

"I was pretty depressed, to be honest, and I wasn't probably a very good person to sort of be around.

"Obviously had some really hard days there, some really dark times, but I was lucky enough to have some really good people around me."

Day also became a father last year, with he and wife Kel welcoming son Danny, and he paid tribute to his young family for allowing him to get back to his best.

"It's a really good distraction and my wife Kel's been amazing, just being able to let me go out and do what I get to do," Day said.

"She's realised how badly it hurt me last year sitting out. How much I want to do well this year.

"I just think it's so selfless of her to put her goals aside and then let me go after mine.

"I've promised her I'll do it for a couple years and then we can get away from the beach and go on holiday at this time of the year."

Day's three wins gives him the lead in the men's series heading into the final three races at Kingscliff in two weeks while Lana Rogers leads the women's series after two wins and a second at the weekend.

Australian Associated Press