Jason Day

The Australian’s ranking slipped as low as 164th last year.

The US player held off England’s Paul Casey, who finished tied for second with Dustin Johnson.

The 23-year-old emerged from a seven-way tie to snatch the lead in California.

China’s Li Haotong holds the halfway lead at Harding Park.

Fleetwood, Rose and Casey are hoping to break the 101-year drought.

Fleetwood carded seven birdies and a solitary bogey at Harding Park.

“Usually when you’re around five under and leading after the first round, it tends to go to around the 10 to 15 under region."

Former world number one Jason Day and American Brendon Todd share the lead.

Koepka is part of a nine-strong group on four under in California.

Tiger Woods is also in the mix after an opening-round 68.