The former World No.1 carded a seven-under 65 on the North Course at Torrey Pines, which included a chip-in eagle on the par-4 7th.

He was tied for sixth at nine-under, four shots off the pace set by co-leaders Jon Rahm, Justin Thomas and Adam Schenk.

Having teed off his second round on the 10th hole, Day's six birdies for the day were capped by an up-and-down on the 9th while his only bogey came at the 2nd.

A two-time champion of the event in 2015 and 2018, Day was pleased with how he finished his round off and is excited to be in contention going into the 'weekend'.

RIGHT: Jon Rahm is part of a three way tied for the Farmers Insurance Open heading into the weekend. PHOTO: Donald Miralle/Getty Images.

"It was a nice chip-in on seven, I was pretty pleased with it," he said.

"Nice to be able to cap it off with a 20-footer on the last."

The event was scheduled for a Wednesday start – rather than the traditional Thursday – and a Saturday finish to avoid a conflict with Sunday's telecasts of the NFL conference championship games.

"Yeah, I know, Friday and Saturday. Either way we're into the weekend and not too far away from the lead hopefully and just give ourselves a chance," the 34-year-old, who has not won in almost four years, said.

Day's fellow Australian Marc Leishman fired a five-under 67 to get to six-under-par while Cam Davis (72) was two shots further back.

At the top, Schenk made eight straight birdies on his way to a career-low, 10-under 62 to sit alongside the top-ranked Rahm (65) and Thomas (63) at 13-under 131.

"I lost track of how many I made in a row, but there was a lot of low scores on the North Course yesterday and I knew there was a lot of gettable holes and I needed to keep going if I wanted to get up on top of the leaderboard and hopefully stay there throughout the weekend," Schenk said.

Rahm birdied five of his first eight holes on Thursday before making his only bogey while Thomas was bogey-free in his sparkling round of nine-under.

Among those to miss the cut were Phil Mickelson, Jordan Spieth, Bryson DeChambeau, Brooks Koepka, Rickie Fowler and Australians Matt Jones and Brett Drewitt.

The final two rounds of the tournament will be played on the South Course.