Manchester United topped the Premier League for the first time in two years following a 3-0 victory over Sunderland on Saturday while morning leaders Manchester City crumbled to a 4-1 defeat at Tottenham Hotspur.
At the other end of the table, Chelsea were indebted to Brazilian duo Ramires and Willian who both scored late on to salvage a 2-2 draw for the champions at second from bottom Newcastle United.
Wayne Rooney ended an 11-match run without a league goal in United's victory at Old Trafford, with Memphis Depay also scoring his first league goal for the club.
Rooney's goal, bundled in 40 seconds after the break, took his league tally for the former European champions to 171, joint third with Denis Law on the club's all-time list.
City's second successive league defeat, after winning their first five matches, meant United moved top for the first time since the opening day of the 2013-14 season.
Louis van Gaal's men now have 16 points, one more than City who took the lead at Tottenham through record signing Kevin de Bruyne before the hosts stormed back with England striker Harry Kane finally on target after 12 hours without a goal for his club.
Arsenal fell behind at previously unbeaten Leicester City but Chile striker Alexis Sanchez returned to his best with a hat-trick in a 5-2 victory that lifted them to fourth with 13 points.
West Ham United are level with Arsenal after drawing 2-2 at home to Norwich City. Tottenham are up to fifth on 12 points.
Struggling Chelsea are sixth from bottom with eight points from seven matches.
"In the first half, from zero to 10, (we were) minus one," manager Jose Mourinho told Sky Sports after the draw at Newcastle. "But in the second half we played very well."
Under-pressure Liverpool manager Brendan Rodgers enjoyed some relief with Daniel Sturridge bagging a double in a nervy 3-2 home win against Aston Villa.
Southampton breezed past Swansea City 3-1 while Stoke City beat Bournemouth 2-1, their first league win of the season.
With Rooney back among the goals and Depay also on target, optimism is growing at Manchester United after going two seasons without challenging for the title.
Depay opened the scoring from Juan Mata's cut-back and once Rooney had doubled the lead there was no way back for rock bottom Sunderland who have only two points this season.
Mata made sure of victory with the third goal in the final minute.
Manchester City manager Manuel Pellegrini refused to blame the match officials for his side's capitulation at Spurs despite the home side's first and third goals being offside. "We didn't play very well against West Ham (last week) in the first half, we didn't play well here in the second half," Pellegrini said.
De Bruyne put City ahead in the 25th minute after a counter-attack led by Yaya Toure who failed to finish the game due to a hamstring injury.
Eric Dier levelled for Tottenham on the stroke of halftime with a low shot although Kyle Walker was several metres offside before crossing in the build-up to the goal.
A header from Toby Alderweireld put Tottenham ahead in the 50th minute before Kane, also looking offside, coolly clipped in a rebound when Christian Eriksen's free kick hit the bar and Erik Lamela completed the rout.
Arsenal fell behind to Jamie Vardy's early strike but Sanchez then became the first player to score a hat-trick in the top flights of England, Spain and Italy.
Theo Walcott equalised before Sanchez put Arsenal ahead after 33 minutes. The Chilean headed his second in the 57th and completed his treble nine minutes from time.
"He is back to his best level," manager Arsene Wenger said of Sanchez. "I could see in training a different player in the last week or two and he has shown that today."
The fifth Arsenal goal came from Olivier Giroud deep into stoppage time. REUTERS