Mario Balotelli scored the winner with a stoppage-time penalty as Premier League leaders Manchester City beat title rivals Tottenham Hotspur 3-2 but Manchester United remained snapping at City's heels with a 2-1 victory at Arsenal.
City's 100 percent home record seemed about to end after Tottenham recovered from a two-goal deficit in a mad nine-minute spell midway through the second half.
Balotelli, who Spurs manager Harry Redknapp felt should not still have been on the pitch after appearing to stamp on Scott Parker earlier, converted calmly to send the packed stadium into raptures.
City moved to 54 points from 22 games, with second-placed Manchester United on 51. Spurs stay third with 46.
United made it another Manchester double over north London when they won a rather less dramatic but equally exciting game at the Emirates to leave Arsenal a distant fifth after a third consecutive league defeat.
The two Manchester clubs beat Spurs and Arsenal by a combined goal tally of 13-3 on the same weekend in August and United followed City's fortunate win over Spurs with goals from Antonio Valencia and Danny Welbeck sandwiched either side of Robin van Persie's equaliser for the home side.