Jason Day is tied for the lead after 54 holes of a major.

Been there before.

Yet, unlike at last month's U.S. Open, Day is feeling good about his chances heading into the final round as he looks to win his first major title at the British Open.

A month ago, the Australian managed to haul his weary body into the final pairing at Chambers Bay despite collapsing because of vertigo in the second round and suffering bouts of dizziness in the third. Unsurprisingly, he faded out of contention and closed with a 74.

It's a new Day at St. Andrews. Back fit and in full control of his body, he was bogey-free Sunday in a 5-under 67 that put him tied with South Africa's Louis Oosthuizen and Irish amateur Paul Dunne on 12-under 204.

"To be able to come back pretty much three weeks later and play the way I've been playing ... I feel healthy and I feel up to the challenge," Day said.

He'd better be.

Day will be playing in the second-last pairing alongside Jordan Spieth, an American who is 18 holes away from the third leg of a Grand Slam. Spieth is a stroke back in fourth place and "heavy favorite" for the title, according to Day.

"Everyone knows it," Day said. "He's just playing phenomenal golf. If you look at the run that he's had this year, it's been amazing."

Just don't see that view as a sign of weakness from Day.

The 27-year-old Queenslander is relishing the opportunity to become the first Australian since Greg Norman in 1993 to lift the claret jug, something he believes would put him in a group of "immortal" players.

Day said he'd learnt lessons from a bunch of near misses at the majors, starting at the U.S. Open in 2011 when he tied for second behind Charl Schwartzel. He had a share of the lead late on Sunday at the Masters in 2013 until he missed out on the playoff between Adam Scott and Angel Cabrera, and he finished tied for second at the U.S. Open later that year.

Then came Chambers Bay, where — somehow — he was tied with Branden Grace, Dustin Johnson and Spieth with 18 holes remaining.

Day said he will need to engage more with his caddie, Colin Swatton, before shots and be "fully involved in the process" of each shot.

In short, have more clarity under the most extreme pressure.

"In previous starts where I was in contention, I was kind of out of sync," Day said. "I wasn't really talking to Colin that much. I was just getting up there and trying to hit it on the run."

Four words uttered by Tiger Woods will also be a source of inspiration for Day in his latest bid for a major.

They were in the same group for the first two rounds and chatted as they walked down No. 18 late Saturday. As they walked off the green minutes later, Day said that Woods shook his hand and told him: "Go get it done."

"To be able to hear that come from that person, it gives you a boost of confidence just to know that you're doing the right things," Day said, "that someone that good really believes in your skills."

After completing a round that contained five birdies and a missed 8-foot putt for another birdie on the last, Day let his mind wander back to the 18th hole and the "best walk in golf." Over the famed Swilcan Bridge, up the fairway and toward the clubhouse with St. Andrews Bay in the distance.

"That little piece of immortality and glory that comes with winning the claret jug at the home of golf at St. Andrews," Day said, "it would be an unbelievable piece of experience that no one could ever take away from you."