It was a crazy Saturday night of football that started with a draw in the Merseyside derby before Real Madrid and Barcelona's embarrassment in La Liga took hold of discussions.
Sterling made the difference in a tactical encounter to condemn Arsenal to their second defeat of the season, AC Milan's Zlatan Ibrahimovic scored an early brace to secure a 2-1 win over neighbours Inter in the Serie A derby, Chelsea were held to a 3-3 draw by a spirited Southampton side, Bruno Fernandes made amends for a missed penalty with a late strike as Manchester United thrashed Newcastle United 4-1, Serie A champions Juventus were held to a 1-1 draw at promoted Crotone and Bayern Munich's Robert Lewandowski and Thomas Mueller scored two goals each as the German champions crushed hosts Arminia Bielefeld 4-1 in the Bundesliga in an eventful night.
But in the end Barca and Real lost for the first time this season, increasing the doubts over their stalled attacks ahead of Champions League openers and their own Clasico clash. Both the games were in Madrid, at venues 30km apart, and both Real and Barcelona were wearing pink.
Barcelona had a first defeat under Ronald Koeman when they lost 1-0 at Getafe, soon after Madrid were beaten 1-0 at home by newly-promoted Cadiz.
It was Los Blancos' first La Liga loss in 15 games.
Barca superstar Lionel Messi was not rested for the clash, but the Argentine failed to make an impact as the star-powered attacks of the European powerhouses appeared shackled by their opponents.
While Getafe lived up to their reputation as one of Spain's top defensive sides by shutting down Barcelona, Madrid were sloppy and sluggish against an inspired Cadiz, who came back to the top flight after 15 seasons.
Madrid had perhaps the more concerning display, the reigning champions managing just two shots on target against Cadiz. But Barca were not much better, with Lionel Messi strangely quiet and the team failing to rebound after Jaime Mata's penalty gave Getafe the lead.