Rory McIlroy described completing the Grand Slam earlier this year as "climbing his Everest", but how hard is the challenge to reset after such a career-defining success?
McIlroy became just the sixth player in the men's game to complete the Grand Slam after ending his 11-year wait for a fifth major title at The Masters, although has since admitted to "lacking motivation" in events since his play-off win at Augusta National.
The world No 2 failed to contend at the PGA Championship and missed the cut at the RBC Canadian Open, with McIlroy admitting that he "didn't really care" about whether he made the cut as he stuttered into the weekend at the US Open.
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He posted a final-round 67 at Oakmont Country Club but still saw his week finish before the final group had teed off, with the 36-year-old admitting he needed to get in "the right frame of mind" for The Open and the remainder of the season.
Rich Beem reached his career milestone by holding off Tiger Woods to win the 2002 PGA Championship, his third and final PGA Tour title, with the former major champion relating to many of the struggles that McIlroy has been experiencing.
"It [McIlroy] kind of brought me back to what happened to me," Beem told Sky Sports. "It's not quite like Rory winning the Grand Slam, but I guarantee I went through a lot of the same emotions I think he's going through right now.
"I chased the money at the end of the season, I didn't finish the season very well, then I had two or three weeks at the end of the last event before I had to go back out to the Mercedes Championships [now The Sentry].
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"When I stood on that first tee I hated everything about golf. I hated wanting to be there, hated the fact I had to be there and felt like I should be there, when in fact I wanted nothing to do with it.
"It had nothing to winning the biggest tournament of my life, something I never expected to win or even thought about winning. I was so angry on that tee box, not just about the game of golf, but with the smallest thing. It was all consuming.
"Why didn't I feel like the person I should feel like after winning one of the four great tournaments? It was the first time in my life where I felt I wasn't in control of my emotions, where I needed to go talk to a sports psychologist.
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"I got to the point where I couldn't handle being around anybody or anything and the last place I wanted to be was at a golf course. I can understand why Rory might be in this position. It doesn't look or feel like he really wants to be in or around this game right now."
Scheffler: Hard to describe toll of major victory
Scottie Scheffler came into the US Open with three wins in his previous four starts, including an impressive victory at the PGA Championship, although previously took time to adjust to being a major champion.
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Scheffler claimed his maiden major title at The Masters in 2022 - his fourth win in six starts on the PGA Tour - but didn't win again for another 10 months, with the world No 1 understanding some of the thoughts and challenges McIlroy may be facing.
"There's definitely an aspect of having an achievement that you've thought about for a long time and then being able to achieve that goal," Scheffler explained. "I mean, winning a major championship in general just takes a lot out of you.
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"Physically and mentally it's a pretty taxing thing to do. It's really hard to describe to somebody that hasn't really lived through it just because - I mean, when I woke up after the PGA Championship this year, I literally felt like I got hit by a bus. I felt terrible.
"It's just part of the adrenaline, part of competing for four days on a really difficult golf course, keeping your head in it for 72 holes, which is a long time, and just mentally it's exhausting. Physically, it's a grind too.
"If that's how I felt after the PGA Championship, I can only imagine how Rory felt after winning the career Grand Slam. It's not easy to show up every week out here and play well."
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McIlroy searches for 'right frame of mind' - is the best yet to come?
He played his best golf of the week during Sunday's final round at Oakmont, where a three-under 67 matched the lowest of the day, with McIlroy enjoying improvements off the tee after struggling with his driver in recent starts.
McIlroy remains in contention to claim a record fourth FedExCup victory, despite his post-Masters dip, with Dame Laura Davies backing him to rediscover his motivation and challenge for more major success in the years ahead.
"At some point he'll think, 'I want more majors', whether it's five, 10 or 12, whatever that number may be, and he'll get back on it," Davies told Sky Sports.
"The start of his year was sensational with the wins, The Masters obviously being the high point. He looked invincible for a while and you don't just lose that. It's not like he's lost confidence, he's just not as focused as he was before.
"We certainly have not seen the best of Rory McIlroy and only time will tell. As soon as his focus comes back you get the feeling he'll be back at it."
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What's next for McIlroy?
McIlroy has committed to playing the Travelers Championship on the PGA Tour next week, the Signature Event that he sat out of last year after narrowly missing out on US Open victory to Bryson DeChambeau.
He is also listed to play the Genesis Scottish Open from July 10-13, the week before he plays The Open on home soil at Royal Portrush.
Throw in the FedExCup Playoffs, the Amgen Irish Open, the BMW PGA Championship and the Ryder Cup - all live on Sky Sports - and there's still plenty for McIlroy to look forward to over the coming months. Get Sky Sports or stream no contract on NOW.