The five-time major champion needed birdies on his final two holes to become just the 11th player to record a sub-60 round on the PGA Tour but a par on 17 scuppered his chances.

A birdie on 18 left him one stroke shy of the mark and four shots ahead of Curtis Luck after the young West Australian’s opening round of 64.

The round of 12-under at the La Quinta Country Club still represents the 48-year-old American's lowest score in relation to par.

Mickelson's flawless round came as he started his 27th full season as a professional.

“Sometimes you have those days where it all clicks,” he said.

“The bad shots I hit I was able to get away with and didn't have the big score. And I made a lot of birdies.

“It was a fun day but I certainly did not expect this to be the case.”

RIGHT: Luck’s round of 64 left him four back of Mickelson at the Desert Classic in California. PHOTO: Jeff Gross/Getty Images.

Luck, 22, missed three consecutive cuts before Christmas but it didn't take him long to find his touch in 2019.

Playing in his first full PGA Tour season, Luck had three consecutive birdies on the front nine and eight for the day in a bogey-free 64 at the La Quinta course that in other circumstances, might have seen him in the lead.

As it happened, veteran Mickelson made everything including chip-ins to shoot a remarkable opening round.

The Desert Classic is the only PGA Tour event to yield two sub-60 rounds.

David Duval had a 59 at PGA West's PGA West's Palmer Course when he won in 1999. Adam Hadwin shot 59 at La Quinta in 2017.

Top-ranked Justin Rose, also making his 2019 debut, had a 68 at La Quinta – one of three courses used in the event.

He's the first No.1 player to play the tournament since the world ranking began in 1986.