Overview
- Real Madrid beat Marseille 2-1 at the Bernabéu, with 18-year-old Franco Mastantuono starting on his Champions debut and Kylian Mbappé scoring both goals from the spot before Dani Carvajal was sent off.
- Juventus and Borussia Dortmund shared a wild 4-4 draw in Turin, with the hosts salvaging a stoppage-time equalizer after trailing late.
- Arsenal opened with a 2-0 victory away to Athletic Club in San Mamés to bank an early three points.
- Tottenham edged Villarreal 1-0 in London thanks to an own goal by goalkeeper Luiz Júnior on his Champions League debut.
- Union Saint‑Gilloise stunned PSV 3-1 in Eindhoven, and Qarabag rallied to beat Benfica 3-2 in Lisbon after the hosts led 2-0.