Retired Australian tennis star Sam Groth believes Nick Kyrgios has the talent to win Wimbledon, but says he doesn't know if he has the mental strength to claim his debut Grand Slam title in 2018.
Kyrgios goes into this year's Wimbledon on the back of some great grass court form, with strong showings at Stuttgart and Queens.
The 23-year-old made it to the last four of each lead-up tournament, going out of Stuttgart to Roger Federer 7-6(2) 2-6 6-7(5).
At Queens, the Aussie earned wins over Andy Murray and Kyle Edmund, before taking eventual champion Marin Cilic to tiebreaks in a two-set loss.
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Ranked 19th in the world, Kyrgios has enjoyed some good results in best-of-three set tournaments, but hasn't been able to parlay that into the same success at the majors.
His best Wimbledon performance was a stunning quarter-final run in 2014 when he beat Richard Gasquet and Rafael Nadal.
Kyrgios will play veteran Denis Istomin in the first round, with a potential showdown with Bernard Tomic in the third round.
The Aussie has won both of the matches he's played against Istomin, including a straight-sets win at the French Open in 2015.
Speaking on Fox Sports, Groth said Kyrgios has the tools to win the tournament, but echoed the thoughts of many by questioning whether he has the mental fortitude to get the job done.
"He comes in with good form, he made the semis in Queens, semis in Stuttgart and lost to the two eventual champions in Federer and Cilic - who we talk about their prospects of winning the title," he said.
"I know a lot of people at Wimbledon are talking about where Nick's fallen in the draw - being able to make it through to a semi-final against Rafael Nadal.
"Everyone believes he has the talent, it’s all about what goes on up here a little bit, and can he put together enough matches to push himself deep in the tournament?
"His best tennis he can there, but mentally, I don’t know."
Second seed Nadal is also on that side of the draw, along with Alex Zverev, Kei Nishikori, David Goffin, Andy Murray and Juan Martin del Potro.
"Nick's tennis is good enough to compete with any of those top guys," Groth said.
"He's one of the few guys to have beaten the Big Four - Nadal, Federer, Murray and Djokovic - and his best tennis is good enough to take him deep into the tournament.
"It's a lot of best of five-set matches, and Nick's problem has been staying interested. Not interested in how hard he tries necessarily, but just staying engaged in the match long enough.
"Over five sets there's massive ebbs and flows and you could be playing for four-and-a-half hours.
"His best tennis is good enough, but can he stay emotionally engaged over the time in a Grand Slam?"