After weeks of work to better align his swing and troublesome back, Day shot a bogey-free five-under 67 in The American Express tournament.

But World No.1 Jon Rahm had warned that the Tour's spate of extreme low scoring was likely to continue this week and so it proved.

Patrick Cantlay and Lee Hodges took full advantage of perfect weather and turf conditions on Thursday at La Quinta Country Club to shoot 10-under 62s and take a two-shot lead.

World No.4 Cantlay has been in rare form.

He won the BMW Championship and Tour Championship in his final two starts last year as he claimed the FedExCup and he opened this year with a fourth-place finish at the Tournament of Champions in Hawaii, where Cam Smith won at 34-under.

RIGHT: Lee Hodges shares the lead with Cantlay after a 10-under round on Thursday. PHOTO: Sam Greenwood/Getty Images.

He played the first seven holes in seven-under, making an eagle on the par-5 sixth and five birdies, then added birdies on Nos.11-13, two of them par-5s, and closed with five straight pars.

"I got off to a roll at the start and kind of made a bunch of putts and then I kind of lagged on the way coming in," Cantlay said.

"But I was happy with everything. I thought I did everything well and it's a golf course I really like. It's in perfect shape and so, if you get the ball rolling on line, it should go in."

Hodges made a memorable debut in the event. The former Alabama star played the back nine at La Quinta in seven-under 29, eagling the par-5 fifth and making five birdies.

"It's one of my favourite golf courses I've ever played, to be honest," Hodges said. "I played it I guess three times now and it's spectacular. It's like hitting off of mats half the time. It's just in perfect shape."

Day played his round on the Nicklaus Tournament course, one of three in use for this event.

Fellow Australian Brett Drewitt also played that course and shot 65, with the pair tied for 24th.

Cameron Young and K.H. Lee were tied for third at 64. Young played at La Quinta, and Lee on the Stadium Course.

Top-ranked Jon Rahm and Graeme McDowell were in the group at 66, both playing at La Quinta.

"I liked the score and the weather," Rahm said. "It's always a very enjoyable walk out here. La Quinta Country Club it's a great golf course. It's always in pristine shape, one of the best we play all year shape-wise."

Tournament host Phil Mickelson was tied for last in the 156-player field after a 78 at La Quinta.

He made a quintuple-bogey nine on the par-4 eighth after hitting two drives out of bounds right.