Real Madrid began the 2025-26 La Liga campaign with a narrow 1–0 home victory over Osasuna, sealed by a Kylian Mbappé penalty in the 51st minute at the Santiago Bernabéu. The French forward, now wearing the No. 10 shirt, earned and converted the spot-kick after being brought down by defender Juan Cruz. In his first competitive match in charge, coach Xabi Alonso fielded several summer signings, while 18-year-old Argentine midfielder Franco Mastantuono made his official debut from the bench. Despite dominating possession, Madrid failed to add to the lead, forcing goalkeeper Sergio Herrera into only a handful of saves. Osasuna’s hopes of a late equaliser faded when left-back Abel Bretones was sent off in stoppage time for a challenge on Gonzalo García. Madrid leave the opening weekend with three points but with room for improvement before visiting newly promoted Real Oviedo on 24 August.