In a shocking night of Champions League football, defending champions Real Madrid suffered a surprising 3-1 defeat at home to AC Milan, marking their third consecutive loss in the tournament. Meanwhile, Manchester City squandered an early lead to lose 4-1 against Sporting Lisbon, with Erling Haaland missing a critical penalty. Sporting's Viktor Gyökeres starred with a hat-trick, showcasing his exceptional form as the team celebrated their coach Rúben Amorim's last home game before taking over Manchester United. In contrast, Liverpool enjoyed a dominant 4-0 victory against Bayer Leverkusen, with Luis Díaz scoring a hat trick to propel them to the top of the league phase table. The results have significant implications for the standings, with Real Madrid currently sitting 17th out of 36 teams. This day of upsets also saw Celtic defeat RB Leipzig 5-1, adding to the excitement of Matchday 4.