High-flying West Bromwich Albion inflicted Chelsea's second loss of the Premier League season, and Manchester City recorded the biggest win of its title defense by beating Aston Villa 5-0 on Saturday.
West Brom rose to fourth, just a point and a place behind Chelsea, by beating the European champions 2-1.
Ahead of Manchester United's match at Norwich, City rose to the summit after Sergio Aguero and Carlos Tevez each scored twice after David Silva's opener against Villa.
In the north London derby, Arsenal beat Tottenham 5-2 after Emmanuel Adebayor's sending off swung the game in his former team's favor.
The pressure increased on Queens Park Rangers manager Mark Hughes after his winless side lost 3-1 to Southampton to stay bottom. Reading secured its first win, beating Everton 2-1.