The 36-year-old fired a seven-under round of 65 to secure the win ahead of Spain's Jon Rahm, who led for most of the tournament, and American Brandt Snedeker (SC) at Torrey Pines on Monday.

His final score saw him finish at 17-under the card, one shot ahead of the Spaniard. He hit rounds of 68, 72 and 68 in the opening three days.

Leishman's last win on the PGA Tour came back in October 2018 when he was victorious at the CIMB Classic in Malaysia.

His other wins on the highly-competitive pro tour were the 2012 Travelers Championship, the 2017 Arnold Palmer Invitational and the 2017 BMW Championship.

"It's amazing and anytime you can win it's special," he said after taking out the win.

"To win here where I have come close a number of times... it's a place I love coming to and on Australia Day is pretty amazing. I was really happy that I could shoot a good score today.

"Particularly all the problems that have been happening back in Australia with the fires and people losing their lives, firefighters. Just devastating really.

"If this can bring them a little bit of joy, that's a big win for me personally and then for them as well."

Jason Day, a two time champion, is the only other Australian to win at the tournament.

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Starting the final round four shots behind the lead, the world No.28 birdied four of his first seven holes before adding two more on par-3s at the eighth and 11th.

The father-of-three finished the back nine with a birdies on the 13th and the 18th with his only slip up of the final round coming on the 17th when he bogeyed the hole.

Leishman, who had finished runner-up at the tournament in 2010 and 2014, saved his building momentum on the par-4 12th with a clutch put for par.

Leading by three shots, Leishman hit his tee shot into thick rough before eventually nailing a 20-foot putt to level the hole.

The Warrnambool product hit 14 of 18 greens in regulation during his final round but he only managed to land three of his tee shots on the course's 14 fairways.

"I didn't hit it that well off the tee today but I putted as good as I ever have today and you're not going to win tour events if you don't putt well," he said.

Already 28th in the world and the second highest Aussie coming into the week, Leishman is likely to represent Australia at the Tokyo Olympics this summer.

With the victory, he also locks up his PGA Tour membership up until the end of the 2021-22 season.

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