Free-scoring Arsenal replaced Chelsea as Premier League leaders with goals either side of halftime by Theo Walcott and Mesut Ozil helping them recover from a slow start to beat Stoke City 3-1.
Jamie Vardy burst back to his predatory best with his first Leicester City hat-trick as the champions recaptured their title-winning mojo to earn a shock 4-2 win over Manchester City at the King Power Stadium.
Vardy, hero of last season's fairytale triumph, finally ended his 16-match goalscoring drought for the club by scoring twice in the first 20 minutes as the Foxes, making a nonsense of their miserable recent form, raced into a three-goal lead.
Despite his heroics for Leicester, Vardy had never scored a hat-trick for them and his last treble had been for minor league Fleetwood in 2012.
Meanwhile it took Charlie Adam's 29th-minute penalty for Stoke to spark Arsenal into life but once they shook off their early lethargy they were irresistible, taking their goal tally to 12 in eight days.
Substitute Alex Iwobi's strike late in the second half gave Arsenal the two-goal margin they required to knock Chelsea off the summit, for 24 hours at least, by virtue of having scored four more goals than their London rivals.
The Gunners, who have 34 points from 15 matches, are unbeaten in the Premier League since the opening day of the season and are heading into the hectic holiday period on a roll.
In other results Watford beat Everton 3-2, Burnley beat Bournemouth 3-2, Swansea beat Sunderland 3-0 and Hull and Crystal Palace drew 3-all.
Arsenal and Chelsea have 34 points, Liverpool and manchester City 30, Tottenham 27, manchester United and Watford 21.
Tomorrow Chelsea play West Brom, Manchester United play Tottenham, Southampton play Middlesbrough and Liverpool play West Ham.