London:Arsenal was stunned 2-1 by Premier League newcomer Hull, and the season's biggest upset so far could prove costly with title rivals Manchester United, Chelsea and Liverpool all winning 2-0 on Saturday.
Daniel Cousin headed in a 66th-minute winner to clinch a famous victory for 104-year-old Hull in its first campaign in the top flight.
Arsenal's second defeat in 60 league matches at Emirates Stadium knocked Arsene Wenger's side off the summit, with the Gunners now two points behind leaders Chelsea and Liverpool - and just one point ahead of Hull.
"I'm more disappointed than worried," Wenger said. "With this kind of game, when you lose them you try to analyze first why, and then you respond in your next game."
Fernando Torres ended his six-game Liverpool goal drought in the victory over crosstown rival Everton, and Man United striker Wayne Rooney scored for the first time since April against Bolton.
Jose Bosingwa and Nicolas Anelka gave Chelsea a 2-0 win at Stoke, while Aston Villa went third by beating Sunderland 2-1.
Newcastle slumped to its fifth loss in a row with Blackburn winning 2-1. Gianfranco Zola won his second league match as West Ham manager 2-0 at Fulham, and West Bromwich Albion beat Middlesbrough 1-0.
Arsenal ended 51 minutes of frustration when Hull defender Paul McShane nudged the ball into his own net amid pressure from Cesc Fabregas after Theo Walcott had dribbled through the defense and combined with Emmanuel Adebayor.
Geovanni spectacularly leveled in the 62nd, striking a 30-meter (yard) shot that beat goalkeeper Manuel Almunia.
Hull wasn't content with its point and produced the winner four minutes later.
Daniel Cousin saw Kolo Toure deflect his shot wide, but from Andy Dawson's resulting corner the Gabon forward headed in his first goal since arriving at Hull from Rangers last month.
"I can't quite believe it, but the reality is I'm here and trying to take every game as it comes and enjoy the experience at the moment," Hull captain Ian Ashbee said. "We went for it, we played with three strikers. We could have come and try to shut up shop, but we knew that would be difficult against Arsenal."
In the 208th Liverpool derby, Robbie Keane crossed the ball into the box for Torres to volley home in the 59th.
Keane was also the architect of the second goal three minutes later, slotting through to Dirk Kuyt. He was tackled by Phil Jagielka before he could shoot, but the loose ball fell for Torres to fire past Tim Howard.
"Six games is too many times for a Liverpool striker (to not score)," Torres said. "Now I want to keep going in the Champions League, scoring almost every game like last season and maybe improving on the 33 goals (from last season)."
Three minutes later, Liverpool had two goals disallowed in quick succession.
Kuyt's effort had only just been ruled out, when Torres' hat-trick celebrations were short-lived. Referee Mike Riley had spotted Kuyt fouling before Torres found the net from an acute angle in the 66th.
Everton midfielder Tim Cahill's 80th-minute red card was the eighth dismissal in the last eight Liverpool derbies.
Bosingwa put Chelsea ahead in the 36th with his first goal since moving from FC Porto in the offseason, slotting in from an angle as defender Andy Griffin failed to clear on the line.
Bosingwa set up Anelka's 76th-minute goal when Leon Cort failed to clear his cross.
Man United won its first home match of the season, but had been frustrated throughout the first half by Bolton goalkeeper Jussi Jaaskelainen.
Cristiano Ronaldo grabbed a contested opener from the penalty spot in the 60th, with referee Rob Styles penalizing Jlloyd Samuel for sliding into Ronaldo, despite appearing to get the ball.
It was a "nonsense decision," according to Bolton manager Gary Megson, and Alex Ferguson seemed to agree, calling it a "little break."
"I was surprised," the United manager said. "It looked to me as if the Bolton player got a foot on the ball. But Rob Styles turned down four or five for us last season, so maybe we're getting payback now, but he still owes us four!"
Rooney came off the bench to send a curling shot past Jaaskelainen in the 77th.
Aston Villa rallied after Djibril Cisse put Sunderland ahead in the 10th, with Ashley Young leveling inside eight minutes and John Carew snatched the winner in the 33rd.
West Ham scored two goals in the last three minutes of the first half, with Carlton Cole and Matthew Etherington finding the target. Fulham striker Andrew Johnson was then sent off just before the break.
Danny Murphy converted a penalty in the 59th for Fulham.
Newcastle provided nothing to encourage potential buyers as owner Mike Ashley tries to sell the club after 14 months.
The Magpies were trailing Blackburn at halftime thanks to goals by Christopher Samba (31) and Roque Santa Cruz (41).
Newcastle captain Michael Owen scored for the fourth time in six games, but his 48th-minute penalty couldn't inspire a comeback as the club continues to reel from Kevin Keegan's resignation three weeks ago.
Jonas Olsson scored in the 53rd to give West Brom its second victory since returning to the top flight.
Tottenham goes to Portsmouth on Sunday in search of its first league victory of the season, while Manchester City makes the short trip to Wigan as it looks to bounce back from an embarrassing midweek League Cup defeat to second-tier Brighton.