Manchester City moved one point ahead of Manchester United at the top of the Premier League on Saturday as City recorded the biggest win of their title defence and Norwich proved too much for Alex Ferguson's side.
City defeated Aston Villa 5-0 to jump ahead of their rivals, who were defeated 1-0 at Carrow Road.
It was a miserable return to West Brom for Chelsea manager Roberto Di Matteo as the European champions lost 2-1 and his former side went just a point behind them in fourth.
In the early game of the day, Arsenal defeated Spurs 5-2 in the North London derby after goalscorer Emmanuel Adebayor was sent off for an early challenge on Santi Cazorla.
The pressure increased on Queens Park Rangers manager Mark Hughes after his winless side lost 3-1 to Southampton to stay bottom. But Reading secured their first win, beating Everton 2-1, while Luis Suarez scored twice in Liverpool's 3-0 win over Wigan and Swansea won 2-1 at Newcastle.
Reigning champions City are the only unbeaten team in the league. Roberto Mancini's side took until the 43rd minute to take the lead, with Silva tucking the ball into the net from close range after Villa failed to deal with Samir Nasri's corner.
But City were far more ruthless after the break, with Aguero netting from the spot in the 54th after Andreas Weimann handled.
City were awarded another penalty 10 minutes later when Barry Bannan handled and Tevez converted his spot kick.
Aguero was on target again, with the Argentina striker scoring from a tight angle after bursting into the penalty area.
Tevez completed the rout by grabbing his second, tapping in from close range after being picked out by Nasri. The result plunged Villa into the relegation zone.
Norwich did what many teams in the league have failed to do against Man United - keep the lead.
The 1-0 loss was United's third defeat of the season and moved them into second. The win moved Norwich up to 13th.
Anthony Pilkington, who was once a youth player at United, put the Canaries ahead with a superb header on the hour at Carrow Road. Norwich then put bodies in the box to successfully defend their lead with United rarely looking a serious threat.
United were below par and appeared to miss the energy of striker Wayne Rooney who is out through injury.
Chelsea had been in control of the Premier League in the opening weeks but have slipped to third and are on a four-game winless run.
Shane Long put West Brom in front a day after his grandmother died and revealed an 'RIP Nan' t-shirt after heading in James Morrison's cross in the 10th.
Eden Hazard levelled before halftime, heading in his fourth goal of the season, but Peter Odemwingie nodded in West Brom's winner after the break from Long's cross.
Everton dropped to fifth after losing at Reading despite Steven Naismith putting the Merseyside club in front.
Adam Le Fondre headed Reading level in the second half and then netted the winner from the spot after being fouled by Seamus Coleman. The victory moved Reading up to 17th place with nine points and out of the relegation zone on goal difference.
Southampton remain in the drop zone but moved four points above QPR who extended their winless run to 12 matches.
Rickie Lambert, Jason Puncheon scored for Southampton and after Junior Hoilett pulled one back, QPR defender Anton Ferdinand scored a late own goal.
Liverpool rose to 11th place after Suarez scored twice in nine second-half minutes and then played a part in the third which saw Jose Enrique score his first goal for Brendan Rodgers' side.
In another mid-table meeting, Swansea won at Newcastle for the first time since 1980, with goals from Miguel Michu and Jonathan de Guzman securing a 2-1 win. Demba Ba scoring a consolation goal in stoppage time.