Winless on the PGA TOUR for more than three years, without a top-five since last August and fresh off missing his first US Open in a decade, the confidence Day has spoken of all year seemed misguided.

Yet the decision to put his TaylorMade Spider putter back in the bag and ongoing stiffness related to the back injury that forced his withdrawal from the Memorial Tournament three weeks ago somehow elicited a round of 8-under 62 on Friday for a one-shot lead at the halfway mark of the tournament.

A double-bogey at the par-4 10th in his opening round saw the 35-year-old open the tournament with a 1-under 69 but he wiped that sour memory from his mind to go out in 32 and then surge up the leaderboard across the TPC Rover Highlands front nine.

Birdies from two and 13 feet at the first and second holes respectively were followed by a tap-in birdie at four and then a 36-foot bomb at the par-3 fifth. His eighth and final birdie of the day came from 12 feet at the par-4 seventh to post 9-under through 36 holes and a one-shot lead from three-time champion Bubba Watson and Kramer Hickok.

“Sometimes when you do have sort of an injury or stiffness, even if you’re sick, sometimes

you can come out and play some good golf,” was Day’s reasoning but his somewhat surprising position through two rounds.

“It’s sore to get onto the other side of the golf swing, so any time going left was a little bit sore.

“It is what it is. I haven’t had time to really rest it since I kind of put it out. Having a couple weeks off was great, but you just need a little bit more time.

“I was fortunate enough to not really get in my own way today. Hit a lot of good quality drives and my tee to green was pretty solid, I thought. Then holed a lot of crucial putts out there.”

Without an equipment contract, Day started using a SIK putter last month but said a return to the TaylorMade Spider-style flatstick he used to become one of the game’s best putters brought back some familiar sightlines and more familiar results.

“Just going back to something that felt a little bit more square to me,” said Day, currently ranked No.71 in the world.

“I was looking down at the putter and just wasn’t lining up correctly. To me felt a little bit closed.

“I crossed myself up and wasn’t trusting my line. So going back to the Spider, which sits a

little bit more open for me, I can trust the line that I’m aiming at.

“It’s nice to be able to visualise a ball going in the hole again instead of thinking, Am I going to hole this putt?

“Nice to be able to do that.”

With Day out in front the next best of the Australian contingent are 2021 Olympians-elect Marc Leishman (66) and Cameron Smith (68) in a tie for 20th at 5-under with Cameron Percy and Matt Jones a shot further back after both had 66s in the second round.

A round of 3-under 67 saw Lucas Herbert safely inside the cut number at 3-under with Adam Scott also qualifying for the weekend with consecutive rounds of 1-under 69.