Vitinha, Ruben Neves, Goncalo Ramos and Joao Felix were among those in attendance at the Portuguese FA's Cidade do Futebol complex in Oeiras, on the outskirts of Lisbon, before their own training session.
For the 16-year-old Al Nassr forward, known as Cristianinho, it was another step up the international ladder — and a debut that came at a moment of changing generations.
Coach Filipe Ramos named him in his 23-player squad on November 2nd, three days before his father retired from international football.
The eldest son of Portugal's former captain made his Under-15 debut in 2025 before progressing to the Under-16s, collecting 13 appearances across those two age groups.
Portugal next host Bulgaria and Serbia in the first qualifying round for the 2027 Under-17 European Championship, with the top two teams advancing. All their matches will take place at Cidade do Futebol.
His name ensures scrutiny, but his father has long balanced ambition for his son with an acknowledgement that a famous pedigree offers no guarantee of success.
"Obviously, I'd love for Cristiano Junior to become a footballer and a top-class player like his father," Ronaldo said in 2016, when his son was six.
Remarkable career
Two years later, Ronaldo said in an interview with DAZN that he saw some of the traits that have driven his remarkable career in his son's game.
"He's very competitive, he's just like I was when I was little. He doesn't like to lose. He'll turn out just like me - I'm 100% sure of that," he said.
"I enjoy teaching him a few things, but he'll become whatever he wants to be, and I'll always support him."
Portugal won the Under-16 Vlatko Markovic tournament in Croatia in 2025, with Cristianinho mimicking his father's trademark celebration after scoring in a 3-0 semi-final win over Wales.
The teenager spent time in the youth ranks of Juventus and Manchester United before moving to Saudi Arabia in 2023.
Both now play for Al Nassr, albeit at different levels, with Cristianinho scoring three goals in seven youth matches this season.