Wayne Rooney scored his second successive hat-trick as rampant Manchester United stormed back to the top of the Premier League with a 5-0 win at Bolton just hours after Sergio Aguero's treble briefly lifted Manchester City into first place.
Rooney scored three times in United's 8-2 demolition of Arsenal before the international break and the England forward picked up where he left off to claim the seventh hat-trick of his career.
He converted two crosses from Phil Jones in the first half and then swept home a Ryan Giggs pass after the break to take his goal tally for the season to 10 for club and country.
United's blistering display, which also included two goals from Mexican forward Javier Hernandez, means the champions have now scored 18 goals in their first four matches, a new Premier League record for this stage of the season that keeps them ahead of title rivals City on goal difference.
"We got an early goal and kicked on from there and it could have been more," Rooney said.
"I had a long time to rest and get a good pre-season under my belt. I've stayed free of injuries and it's helped me for the start of the season."
The only downbeat note for United boss Sir Alex Ferguson was an injury to Tom Cleverley, which forced the young midfielder to come off in the first half.
"We kept playing our football. That is what we are here to do. We withstood all the challenges and just got on with it," Ferguson said.
Earlier, Argentinian international Aguero starred as Roberto Mancini's City outclassed Wigan 3-0 at Eastlands with a mesmerising display of attacking football.
The victory maintained City's perfect start to the season and manager Mancini was purring with pleasure after the virtuoso display of Aguero, signed for a club-record £38 million ($60m) from Atletico Madrid this summer.
"They were fantastic strikes. He is an incredible player. He is young and scored three fantastic goals," Mancini said. "He always scored in his career and I hope that can continue here."
In other results on Saturday, Arsenal bounced back from their humiliating defeat against United in their last outing to record a badly needed 1-0 win over Swansea at the Emirates Stadium.
An Andrey Arshavin goal on 40 minutes secured Arsenal's first Premier League win this season, the Russian international punishing a dreadful blunder by Swans goalkeeper Michel Vorm to finish from a tight angle.
"When you get a big score against you, the confidence goes quickly and comes back slowly," Gunners boss Arsene Wenger said.
"You could see that because we had a nervous second half when we didn't score the second goal. We started well and slowly the nerves took over."
We got an early goal and kicked on from there and it could have been more- Rooney
Chelsea moved up to second place after recording their third win in a row with a 2-1 win over Sunderland at the Stadium of Light.
Blues skipper John Terry drove a deflected shot into the net to put Chelsea ahead on 18 minutes after Sunderland failed to clear.
Chelsea doubled their lead on 51 minutes when striker Daniel Sturridge latched onto a ball over the top from new signing Raul Meireles to score.
Sunderland's South Korean international Ji Dong-Won gave the Black Cats hope with a goal in stoppage time.
Liverpool's recent revival ground to a halt as they crashed to an unexpected 1-0 defeat at Stoke.
Stoke edged ahead against the run of play on 21 minutes after Jamie Carragher was adjudged to have hauled down City striker Jon Walters, who stepped up to convert the penalty himself.
Tottenham recovered from their 5-1 home mauling by Manchester City with a 2-0 victory over Wolves at Molineux.
Emmanuel Adebayor, who joined Spurs on loan from Manchester City last month, struck on 67 minutes to put Tottenham ahead after being played in by fellow debutant Scott Parker. Jermain Defoe then made the game safe for Spurs on 80 minutes.
Everton and Aston Villa shared the points in a 2-2 draw at Goodison Park.
Leon Osman gave Everton the lead but Stilian Petrov levelled for Villa on 63 minutes.
Everton's Leighton Baines rifled home from the penalty spot six minutes later, only for Gabriel Agbonlahor to equalise seven minutes from time.