#3 Serge Gnabry (Germany)
Making his first appearance for Germany at a major tournament, Serge Gnabry was a massive disappointment at Euro 2020.
The 25-year-old winger, who came off a modest 11-goal season for Bayern Munich, remarked on the eve of the tournament:
"I want to score a goal in every game. I want to score goals. I didn't quite manage that like I'd imagined with Bayern last season, but this is a different stage, a different team. We've got no (Robert) Lewandowski or (Erling) Haaland in our team, but we have massive quality up front and on the wings."
However, as things panned out, Gnabry couldn't open his account at a major tournament despite playing four games.
He also failed to add an assist to his tally, as Joachim Low's long stint in charge of Germany ended with a 2-0 defeat to eventual Euro 2020 finalists England in the Round of 16.
Die Mannschaft had their moments at Euro 2020, thumping holders Portugal 4-2 in the group stage. But their inconsistency and shortcomings were laid threadbare by an excellent English side.
#2 Bruno Fernandes (Portugal)
Bruno Fernandes was one of the big disappointments in a star-studded Portugal team at Euro 2020.
Despite the defending champions arriving at the tournament with an arguably better side than the one that went all the way at France in Euro 2016, Portugal failed to turn up at Euro 2020.
Bruno Fernandes, like his compatriot Ruben Dias, was coming off a dazzling season, scoring 24 goals and recording 16 assists across competitions.
But at Euro 2020, the 26-year-old was a pale shadow of the player who lit up Old Trafford after his arrival in the Premier League last year.
Fernandes did not play the entire 90 minutes in any of the four games Portugal played at Euro 2020.
The midfielder, who failed to score or record an assist, fared so poorly that he only came off the bench against France in Portugal's third group stage game and in the Round of 16 clash against Belgium.
#1 Kylian Mbappe (France)
After playing a key role in France's triumphant FIFA World Cup 2018 campaign in Russia, Kylian Mbappe had a campaign to forget at Euro 2020.
The PSG attacker, making his debut in the European Championship, was expected to hit the ground running at Euro 2020 after scoring 42 goals in all competitions last season. But Mbappe failed to score a goal in four games at the tournament.
The 22-year-old did provide two assists at Euro 2020. But his missed penalty in the Round-of-16 shootout defeat to Switzerland ended Les Bleus' bid to win a third European Championship title.
Mbappe had only three shots on target all tournament and created only seven chances for his teammates.
The legendary Pele was one of the first to come out in defence of Mbappe after his no-show at Euro 2020.
Mbappe, despite his struggles at Euro 2020, remains one of the game's finest young players and is touted as a future Ballon d'Or winner.
It remains to be seen how the Frenchman will recover from this setback and fare at his next major tournament.