Manchester United replaced Manchester City as Premier League leaders with Wayne Rooney ending an 11-match run without a league goal in his side's comfortable 3-0 win over Sunderland at Old Trafford on Saturday.
After early-season pacesetters City crumbled to a 4-1 defeat against Tottenham Hotspur in the day's early action in north London, United took full advantage with Rooney and Juan Mata adding to Memphis Depay's first Premier League goal for the club on the stroke of halftime.
Rooney's goal, bundled in 40 seconds after the break, took his league tally for United to 171, joint third with Denis Law on United's all-time list of league scorers.
United moved top for the first time since the opening day of the 2013-14 season and for the first time under Louis van Gaal.
They have 16 points from seven games, one more than City who took the lead at Tottenham through record signing Kevin de Bruyne but slumped to their second successive league defeat with England striker Harry Kane on target for the hosts after 12 hours without a goal for his club.
Tottenham are up to fifth on 12 points.
Arsenal fell behind at Leicester City but Chile striker Alexis Sanchez returned to his best form with a hat-trick in a 5-2 victory that lifted them to fourth with 13 points, level with West Ham United who drew 2-2 at home to Norwich City. The result ended Leicester's unbeaten start to the season.
Under-pressure Liverpool manager Brendan Rodgers enjoyed some relief with Daniel Sturridge bagging a brace in a nervy 3-2 home win against Aston Villa.
Southampton breezed past Swansea City 3-1 while Stoke City beat Bournemouth 2-1 for their first league win of the season.
With Rooney back amongst the goals and Depay also on target, optimism is growing at Manchester United after two seasons without challenging for the title.
Depay opened the scoring from Mata's cut-back and once Rooney had doubled the lead there was no way back for Sunderland who have only two points this season.
"That's what we're all playing for. We have to work hard to make sure we stay there," Rooney posted on Twitter.
Man 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.
Record signing De Bruyne put City ahead in the 25th minute after a counter-attack led by Yaya Toure who failed to finish the game after picking up a hamstring injury.
Eric Dier levelled for Tottenham on the stroke of halftime with a low shot, although Kyle Walker had been yards 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 James Vardy's early strike but were indebted to Sanchez who became the first player to score a hat-trick in England, Spain and Italy's top flight leagues.
Theo Walcott equalised before Sanchez put Arsenal ahead after 33 minutes, headed his second in the 57th minute and smashed home his hat-trick goal 10 minutes from time.
