Football's a fickle old game, and no player will have learned that valuable lesson more in recent months than Trent Alexander-Arnold.
Cast your mind back to the start of this season: the Liverpool youngster was one of the best full-backs in the world and was pivotal to the Reds' so-called 'winning machine'.
Such was the quality of the youngster, there was even talk of him moving into midfield given it seemed absolutely absurd that Liverpool and England could waste the talents of one of the best footballers on the planet - alright, that one may be a bit of an exaggeration - by playing him at right-back.
Less than a year on and he's finished. He can't defend, he hasn't got the mind of a defender, he's a glorified right midfielder and he only looks good because Jurgen Klopp's system plays to his strengths - quite the fall from grace.
The 22-year-old was the most high profile omission from Gareth Southgate's England squad for the March internationals earlier this year, leading to speculation his place at Euro 2020 could be in jeopardy.
Having said that, being left out of said squad seemed to have refocused the youngster after a subpar campaign and in the last couple of months he's produced some solid displays, with his winning goal against Aston Villa at Anfield in April a particular highlight.
However, Alexander-Arnold's performance in the 4-2 win over Manchester United on Thursday evening was by far his 'breakthrough moment' - if you can call it that.
The 22-year-old somehow managed to dominate the game from the right-back position, causing Luke Shaw all sorts of problems as he continued to surge forward and create chances for the Liverpool frontline.
He was instrumental in two of Liverpool's goals at Old Trafford, picking out Roberto Firmino with a pinpoint free-kick as the visitors edged ahead before stepping onto the front foot and capitalising on United's sloppy play before Firmino tapped home the rebound from his stinging effort.
Far from the player we've seen over the past few months, Alexander-Arnold was absolutely everywhere, even finding himself in the left-wing position at one point.
Perhaps the standout moment of the youngster's game came as he fired a superb cross-field ball over the top of the Manchester United backline, offering substitute Sadio Mane the opportunity to put the game to bed, though the forward couldn't quite bring the ball under his spell.
Of course, Alexander-Arnold's ability going forward has never really been in question, it's his defensive ability - or lack of - that has caused some to question his status as England's number one right-back.
However, for all the criticism he's received for his defensive displays, the right-back did well to contain the rapid United frontline and rarely put a foot wrong when tasked with shackling Paul Pogba and Marcus Rashford.
Could he improve defensively? Absolutely, though it's easy to forget that at 22 years of age he has plenty of time to grow and develop, and on this type of form it's impossible not to consider him as England's best right-back.