They are reserves at these famous football clubs but, as it turned out in the opening match of the 2018 International Champions Cup yesterday evening, the second stringers ended up playing first fiddle for both Arsenal and Atletico Madrid.
The match ended 1-1 after 90 minutes and had to be settled by a shoot-out, won 3-1 by the Spanish LaLiga side with reserve goalkeeper Antonio Adan scoring the decisive penalty for Atletico.
And, while there were footballers of international calibre like Slovenian goalkeeper Jan Oblak, Gabonese striker Pierre-Emerick Aubameyang and Welsh midfielder Aaron Ramsey playing before 23,095 fans at the National Stadium, it was the young and hungry who made a bigger impression.
Looking beyond his curly hair and obvious resemblance to Chelsea's David Luiz, Arsenal's new signing Matteo Guendouzi could force himself into Unai Emery's plans sooner than later.
Signed for a reported £7 million (S$12.5 million) from French club Lorient earlier this month, the 19-year-old was forceful in the hustle and bustle of midfield as he showed no fear in asking for the ball from his established team-mates.
Similarly for Atletico, their Argentinian strike pair of Luciano Vietto, 24, and Angel Correa, 23, both backups to Antoine Griezmann and Diego Costa, linked up well to stake claims for first-team places.
After weathering an initial storm from Arsenal, Atletico grew into the game and, in the 41st minute, Correa peeled to the right to cross for Vietto to head home the opener.
That was exactly the kind of hunger and performance Rojiblancos coach Diego Simeone wanted.
The Argentinian said: "I'm really happy with the performance of the youngsters. This is a good time to show what they can do. I have been at this club for seven years (as coach) and I've always wanted to show youngsters how big is the jump to the first team.
"Fernando (Torres) and Gabi had left, somebody has to take their roles. They (the reserves) know Koke and the rest (of the World Cup players) will join training on Aug 6. It is important for us to give youngsters opportunities."
But wiping out Atletico's lead was an even more impressive effort from a teenager wearing the No. 55 jersey for the Gunners.
Emile Smith Rowe might not be a household name, but he has been with Arsenal since the age of nine and is already an Under-17 World Cup winner with England.
Rowe, who turns 18 tomorrow, slalomed his way into the heart of Atletico's defence in the 47th minute before firing a fierce shot into the top corner, a strike that had Arsenal coach Unai Emery purring.
The Spaniard said: "I think this is the moment for the young players to show their quality. History has showed that Arsenal always gave opportunities to young players.
"Today, he (Rowe) scored a very good goal and that's very good for the team. His performance is also very good at each training session. But what is important for us is that every player keeps working."
It remains to be seen if Emery will throw the youngster into the deep end when the Gunners take on champions Manchester City in their Premier League season opener on Aug 12.
But, for the moment, Singapore looks like a good test bed for the rookies in a World Cup year that has deprived the ICC of the big stars.