Fairly or unfairly, massive things were expected of Emma Raducanu when she brilliantly won the US Open in New York last year.
Since then, though, things have not gone well. She has struggled to find a coach and found the WTA Tour much more physical than she imagined, resulting in a number of mid-match retirements.
Despite that, many believe that given her talent level it's still only a matter of time before she wins another major.
However, the following list of one-Slam wonders should serve as a warning that it is not necessarily that simple.
Most people only know Sue Barker as a sports anchor on British television, but she was a fine tennis player in her day too.
Barker was a former world number three and even managed to win a Grand Slam at the 1976 French Open.
Like Raducanu when she won the US Open, Barker was a very young player and it was expected her first major would be just the start, but it turned out to be her only.
If there is a male-equivalent warning for Emma Raducanu, then it is probably Michael Chang.
Chang surprised everyone by winning the French Open as a 17-year-old in 1989. In fact, he remains the youngest man ever to win a major.
He went on to have a very decent career, but he never won another Grand Slam tournament. He did lose three more finals, though.
Nobody expected Richard Krajicek to win Wimbledon in 1996, probably least of all him.
He had former champions Michael Stich and Pete Sampras in his way, but after he got rid of them both at the end of the quarter-finals, he just had to beat two unseeded players to win Wimbledon.
Nobody is going to pass up that chance. Well, Tim Henman probably would have, but Krajicek certainly didn't.
It's quite hard not to feel a degree of sympathy for Conchita Martinez, as she was a richly talented player in an era of legends on the WTA Tour.
Martinez played in the 1990s, and that meant Steffi Graf and Monica Seles were in her way. Just as those two moved aside, Martina Hingis came along and decided to win everything instead.
Her won Grand Slam title came at Wimbledon in 1994, which is perhaps surprising given the clay of Roland Garros is traditionally the Spanish tennis stronghold.
Andy Roddick was supposed to the be chosen one. Roddick was the next off the American conveyor belt that had produced Arthur Ashe, Jimmy Connors, Pete Sampras, Jim Courier and Andre Agassi.
It wasn't just expected that he would win multiple majors, it was simply assumed. The fact he could only manage one is one of the biggest surprises in modern tennis.
In many ways, though, Roddick was the victim of shifting sands. He was a product of an era that favoured huge servers, and just as he arrived the regulations changed to lower the ace-count.
His one Grand Slam win came on home soil, at the 2003 US Open. Perhaps Andy Roddick is the clearest warning to Emma Raducanu that you can't assume anything in tennis.
Considering Ana Ivanovic is still just 34 years old, she could conceivably still be fighting for the top honours on the WTA had she wanted to carry on. She hung up her racket back in 2016, though, and has not really looked back since.
The Serbian was a former world number one who maybe should have won more than the solitary Grand Slam title she has to her name - the 2008 US Open.
These days, Ivanovic is perhaps best known for being married to German football legend Bastian Schweinsteiger, with whom she has two children.
Juan Martin del Potro
It is possible that Juan Martin del Potro is one of the greatest 'what if' stories in all of sport, never mind tennis. The Argentinian was a player who had everything but was ravaged by injury like few others.
Thankfully, before his many injuries decimated his game, Del Potro showed what he was capable of by beating Roger Federer to win the US Open as a 21-year-old.
He did reach other final at Flushing Meadows in 2018, but he was never the same player after all those injuries.
Marin Cilic has been considered something of a spent force on the ATP Tour for a few years now, although he reminded us what he is still capable of by reaching the semi-finals of the French Open this year.
Cilic won the 2014 US Open, beating Kei Nishikori in the final, and has reached the final of both Wimbledon and the US Open.
Despite what happened in Paris, it seems highly unlikely the big-serving Croatian has a second major in him now.
At the time of writing, there is absolutely no reason why Dominic Thiem can't win another major and get himself off this list. He is still just 28-years-old and one of the most talented players around.
He has been in four Grand Slam finals, with the only he won coming at the 2020 US Open. Roger Federer and Rafael Nadal skipped that tournament, and Novak Djokovic got himself disqualified in the fourth round, but a major is a major.
Since then, Thiem has struggled badly both mentally and physically, and he currently looks lightyears away from winning another Grand Slam. The talent remains, though, so don't rule him out.
Andy Murray aside, you'd struggle to find a more popular Wimbledon champion than Goran Ivanisevic. He was known as the lovable loser at SW19, losing three finals at his peak in the 1990s.
When he returned in 2001 as at the world number 125 with a wild card, everyone thought it would just be a nostalgia-fuelled cameo.
It was probably the last one he was expected to win, but he won it in some style, beating Carlos Moya, Andy Roddick, Greg Rusedski, Marat Safin, Tim Henman and Pat Rafter on the way. It was, surprisingly, the only Slam he ever won.
Interestingly, Ivanisevic has been a much more successful coach than he was a player, with him coaching two players (mainly Novak Djokovic) to six Grand Slam titles.
Will Emma Raducanu join them?
This is the big question, isn't it? In truth, Emma Raducanu doesn't look even close to winning another tournament right now, never mind a Grand Slam. Then again, she didn't back at the start of qualifying for the US Open that she won either.
Patience is still required, though. Raducanu still has a lot of physical development to do and she definitely has the game to win more majors. Time is obviously on her side too.
However, as we've seen here, there are absolutely no guarantees in tennis, and surer-looking things than Emma Raducanu have failed to win a second major.