Injury-plagued Nick Kyrgios is backing his physical endurance as Lleyton Hewitt challenges his Davis Cup spearhead to step up mentally in his quest for an overdue grand-slam run.
Kyrgios could snare a precious top-16 Australian Open seeding after rising to 17th in the world rankings on Monday after breaking through for his maiden ATP Tour title in Australia at the Brisbane International.
Regardless of his seeding, the enigmatic star is now among the Open favourites, with world No.3 Grigor Dimitrov declaring Kyrgios almost unplayable during his Brisbane semi-final loss to the Canberran.
Kyrgios, though, has arrived at the slams similarly highly rated before, only to flop and mentally and physically break down.
He crashed out in the second round in Melbourne and Paris last year, then the first round in London and New York, a hip injury curtailing his progress at the season's final three majors after he capitulated from a winning position in his Australian Open clash with Andreas Seppi.
Hewitt spent much of December training with Kyrgios and has no doubts the 22-year-old has the explosive firepower and shot-making to go deep in Melbourne - if he can keep his head.
"That's the biggest thing for him and this next week is about freshening up really and getting his body right and getting mentally prepared," Hewitt said on Monday.
"One thing that he really wanted to improve on this year was his grand slam performances.
"He was disappointed with how they were in 2017 and he's going to get his shot in a couple of weeks.
"He's hit enough balls. His ball striking is there a lot of the times and now it's about getting mentally and physically ready to go out and battle.
"To win a slam is not easy. You've got to win seven best-of-five-set matches against absolute quality players.
"So it's not going to be easy for him but if he can survive that first week, anything can happen."
And that's exactly what Kyrgios plans to do.
Despite having his left knee heavily strapped in Brisbane and complaining to the tournament supervisor that the injury, if it worsened, could potentially keep him out of the Open, Kyrgios believes best-of-five-set tennis at the slams will improve his title chances.
"I've played so many best-of-five matches, played a lot of grand slam tennis and I feel best-of-five tennis actually suits my game well," he said.
"For a period of time, (I know) I'm going to play really, really well and it kind of favours the better player ... I definitely feel comfortable."
His confidence flies in the face of last year's efforts, where he showed imperious form in twice toppling Novak Djokovic and reached two tour finals at best-of-three-set events, yet only won two matches at the four majors.
"I'm feeling very confident with the way I'm hitting the ball and playing in high-pressure situations," Kyrgios said defiantly.
"After last year, leaving Australia not doing so well at the Australian Open, having a lot of expectation but not following it up with anything left a bad taste in my mouth."