In October 2018, Donny van de Beek, aged just 21, was starting for Ajax against Bayern Munich at the Allianz Arena. By the end of that season, he had scored 17 goals from midfield, one of which came in a Champions League semifinal at Tottenham Hotspur.
But rather than the next step up in a career that until that point had gone from strength to strength, his move to Old Trafford triggered a decline so sharp that when head coach Louis van Gaal names his Netherlands squad for the 2022 World Cup, there won't be any questions about why Van de Beek isn't included.
The midfielder was told by Van Gaal he needed to "start playing games" after he was initially dropped from the national squad more than a year ago. Now that he is injured, as well as out of favour, there is little prospect of that happening before the tournament starts in Qatar next month.
It has reached the point where Van de Beek has been written off by most United fans as another bad signing. There was hope in the summer that the appointment of his former manager at Ajax, Erik ten Hag, might kick-start his career in Manchester. But Van de Beek has found opportunities just as hard to come by under the new United boss as he did under predecessors Ole Gunnar Solskjaer and Ralf Rangnick. So far this season he has played 19 minutes of football, and speaking last week, Ten Hag said the 25-year-old would first have to impress in training before being considered for a place in the team.
"He had a muscle injury," said Ten Hag after the Europa League victory over Omonia Nicosia. "So it takes a couple of weeks. He's now back on the training grass, so he's outside doing his work but still individual, he's not returning to team training. So we have to wait for that moment."
Van de Beek has got used to waiting. After arriving at United from Ajax, it took Solskjaer more than two months to trust him with a Premier League start in a 3-2 win at Southampton. He was picked for the next league game against West Ham, but after being substituted at half-time at the London Stadium, he had to wait until May to start another game in the Premier League against Leicester at Old Trafford.
Solskjaer's treatment of a player who was on the 30-man shortlist for the Ballon d'Or in 2019 raised questions about whether the Norwegian was ever keen to have him at the club at all. Van de Beek was signed at a time when United were coming under pressure for a lack of ambition in the transfer market, and they were able to tie up a deal quickly after a proposed move to Real Madrid broke down.
A popular member of the squad, his lack of game time baffled some of his teammates, who would regularly make a point of highlighting him in their social media posts whenever he made a key contribution in training or matches.
A loan move to Everton in January was disrupted by a thigh injury, but Ten Hag's appointment at United in the summer was seen as a fresh start with a coach who had got the best out of him at Ajax. Ten Hag initially said he was "looking forward" to working with his former player, but it wasn't long before he was issuing a warning.
"Me as a manager and the coaching staff around him can do everything to set the right conditions so he can perform, but in the end, the player has to do it by himself," he said during United's preseason tour of Thailand and Australia. "It's the same for every player, he has to do it by himself. They have to take responsibility for their performance. Donny has the capability. I have seen it, but he has to prove himself."
Ten Hag insists "chances will come" during a hectic season in four competitions, but it is becoming increasingly likely Van de Beek will have to leave the club, either in January or next summer, to get his career back on track.
Sources have told ESPN that Leicester City are one of those interested, but Van de Beek has a contract at Old Trafford until 2025, with the option of another year, and United would want some kind of return on the €45m fee they paid just two years ago.
Still only 25, there is still time to prove he can be the same player who burst though at Ajax. But time has already run out on his chances of playing at the World Cup, and the clock is ticking on his future at United.