Jason Day is on course to repeat his winning history at Torrey Pines after a stunning second-round fightback placed him well in contention going into the closing rounds of the Farmers Insurance Open.

And Day wasn’t the only contestant getting plenty of attention as Tiger Woods put medical problems and an embarrassing run-in with the law behind him to turn in creditable rounds and just scrape through to make the cut.

The Australian former world No.1 answered his sloppy opening 73 with a bogey-free, eight-under-par 64 on the North course and with a seven under total Day now sits just four shots back of leader Ryan Palmer (67).

“The front side I needed to get off to a good start and that was crucial,” said Day, who rocketed up the leaderboard with six birdies on his front nine.

At 11 under, Palmer will take a one-shot lead into Saturday’s third round over world No.2 Jon Rahm (66), who is the tournament’s defending champion and is coming off a runner-up and a victory in his past two US PGA Tour events.

Jason Day said he was “a little rusty”, but he was razor sharp for the second round.

Day opened the 2015 Torrey Pines event with almost the same scores – 73, 65 – before winning in a sudden-death playoff.

And he’s feeling similarly good vibes going into the third round.

“Everything is shaping up nicely; I drove it great today which gave me a lot of opportunities, and then I putted well,” said Day.

Day’s 73 on Thursday was his first competitive round since coughing up the final round lead at the Australian Open in November.

But he puts it down to rust and says he’s buoyed by the fact Torrey Pines’ difficult South course, on which the final two rounds are played, should stop anyone running away with the tournament.

“The positive of the first round was I made five birdies on the South course, which are tough to come by, and I just mixed it with some rough and silly errors due to being a bit rusty,” said Day.

“I’m looking forward to it because I feel like I’m doing everything correctly.”

Meanwhile, Tiger Woods salvaged a 71 and, at one under, made the 36-hole cut on the number.

The 14-time major winner will play his first weekend rounds at a US Tour event since the 2015 Wyndham Championship.

Next best of the Australians is Cameron Smith, who nearly withdrew on tournament eve with the flu, but shot a 68 to be tied 14th at five under and six shots back of the lead.

Marc Leishman shares 23rd at four under after a 69, while recent Australian Open champion Cam Davis fought hard with a 70 and, at two under, makes his second cut in as many career starts on the US Tour.

At even par, Rod Pampling (74) and Aaron Baddeley (72) were sent home early, alongside former Australian Open winner Matt Jones (78, three over) and Geoff Ogilvy (74, six over).

-AAP