He's one of the few players to have stared down Jordan Spieth and now Jason Day craves another head-to-head duel with the defending Australian Open champion.
With four major championships among 28 US PGA Tour titles between them, the former world No.1s are clear favourites to battle it out for the Stonehaven Cup when the 102nd Open gets underway in Sydney on Thursday.
After a rare winless season in America, Day says upstaging Spieth would be the perfect way to end the drought.
"I would love to play with Spieth on Sunday, (in the) last group on Sunday; that would be the greatest thing," Day said after Wednesday's pro-am at The Australian GC.
It's been more than two years since the pair famously jostled for the 2015 US PGA Championship, when Day finally broke through after three runner-up finishes to land his first career major.
The Queenslander needed a major-record 20-under-par total to keep Spieth at bay and claim the Wanamaker Trophy and knows beating Spieth remains one of golf's greatest challenges.
The 24-year-old boasts a Nicklaus-like three wins, three seconds and a tied fourth in majors since 2014.
If he'd won the US PGA last year, after raising the Claret Jug in spectacular fashion at Royal Birkdale, he would have become the youngest player to complete the career grand slam.
"His mental game is just off the charts," Day said.
"I've said over the last five years, he's probably the most dominant player outside of (world No.1) Dustin Johnson.
"He doesn't have the natural ability such as DJ's length, but he has the mental toughness, probably the best mental toughness out of everyone on the Tour and that's what gets him going.
"He's such a grinder."
Spieth, who won the Masters and US Open, and Day captured three of the four majors in 2015, with both also finishing one shot shy of a three-man playoff at St Andrews.
The American recalls the rivalry with fondness and would love to rekindle it on Australian fairways in the duo's first appearance in the same event down under.
"The 2015 season was a lot of fun," Spieth said of he and Day trading blows.
"Any time I'd throw something at him one week and think I'd have the advantage on him for the player of the year race, (he'd hit back).
"The last three majors of the year, we both had a chance to win on championship Sunday. That's rare to have a few times in a row, especially two people to have the chance."
