65 appearances. Balvedo became the player with the most appearances in a single season across all major leagues in the 21st century. [xueting]

Goal.com reported on July 10th: In the semi-final of the Club World Cup, Real Madrid played against Paris Saint-Germain. Uruguayan midfielder Barreiro made his debut for Real Madrid in this match. 

This is Balved's 65th game in the 2024-25 season. He has surpassed Huarado (from Atlético Madrid, 2009-10 season), Oscar (from Chelsea, 2012-13 season), Mata (from Chelsea, 2012-13 season), and Torres (from Chelsea, 2012-13 season) to become the player with the most appearances in a single season across the major leagues in the 21st century. 

The four players mentioned earlier all played 64 games in that season.