Jason Day’s decision to reunite with coach Colin Swatton has paid almost immediate dividends, with the former world No.1’s putter catching fire in a second-round 64 at the Arnold Palmer Invitational.

Day, 37, split with Swatton, who was both his caddie and coach, in 2020 after a 20-year association that began when Swatton took the then 12-year-old under his wing at the Kooralbyn International School in Queensland

Under Swatton’s guidance, Day became the world’s best golfer and won the 2015 US PGA Championship.

“He knows my game better than anyone,” Day said on Saturday (AEDT) after sinking seven birdies and an eagle in an eight-under round at the Bay Hill course.

With concerns about his putting, Day revealed that he reached out to Swatton earlier this year, and that the pair had spent last week together.

“But I’ve been chatting to him, so I was very fortunate that he was willing to come back on board,” Day said.

“I did a lot of work on my putting last week, I struggled with that this year, (made) some set-up changes with Col, (and) just had him come back on board, which was nice.

“Some of the (putting) stuff that I was doing I was a little cramped, eyes too far over the ball – I’ve always been a person that has had my eyes on the inside of the ball, like a long way. “Just a head position change, a little bit further away, hands, arms up a little bit higher so the shoulders can pitch a lot better or swing a little bit better.

“Speed has improved dramatically since then, (and my) stroke’s improved dramatically.”

Day’s 64 was in stark contrast to his first-round 76. Heading into the third round, he was at four-under, four strokes behind leader Shane Lowry.

“I’m very fortunate to have a good team around me,” he said.

“I did some visualisation work (after round one) for about 30 minutes, trying to get ready for (round two). That attitude adjustment is crucial.

“It’s nice to be able to get off to a good start (in round two) and put that (first) round behind you and get back in the tournament.”

Day’s fellow Queenslander Adam Scott shot a second-round 72 to make the cut at three-over.

However, the two other Australians in the field – Cam Davis (six-over) and Min Win Lee (seven-over) – missed the cut.