Manchester City shredded the meanest defence in English football's top flight by thrashing Tottenham Hotspur 6-0 at home, while Manchester United's surge up the Premier League table stalled after a 2-2 draw at Cardiff City.
Sergio Aguero and Jesus Navas struck twice for City, who have scored 13 goals in their last two home games.
A sixth home win in six put City in fourth place on 22 points. United were poised to move above them when they led Cardiff in south Wales with goals from Wayne Rooney and Patrice Evra.
The visitors were then denied a fourth consecutive league victory when Kim bo-Kyung's late header earned Cardiff a deserved share of the spoils to leave United in sixth spot with 21 points, seven behind the leaders Arsenal.