Inexplicable mistakes by Joe Hart and Gareth Barry gave Manchester City's Premier League title hopes a potentially decisive blow as they lost 3-1 Southampton, who secured their first win under Mauricio Pochettino in style.
City goalkeeper Hart admitted in the build-up that anything but victory at St Mary's would all but end any their hopes of retaining the title, with leaders Manchester United already boasting a nine-point cushion.
Roberto Mancini's side simply did not look like a side in need of a victory, conceding after just seven minutes when Jason Puncheon slotted home.
Hart could have possibly done better with the shot that led to the opener, but there was no doubting his culpability for Southampton's second.
Excellent team interplay put through Rickie Lambert, whose fierce drive squirmed through the England international's grasp, allowing Steven Davis to bundle home.
Edin Dzeko reduced the deficit as half-time approached, although a two-goal lead could have been restored on the stroke of half-time had referee Martin Atkinson not waved away Jay Rodriguez's penalty appeals.
That was soon forgotten, though, as Barry passed into his own goal unchallenged to put Saints on course for a first win since Pochettino replaced Nigel Adkins at the helm.
Frank Lampard issued another timely contract reminder to Roman Abramovich as Chelsea eased the pressure on boss Rafael Benitez with a 4-1 win over Wigan at Stamford Bridge.
Lampard lashed his 198th career goal for the Blues in the 86th minute to settle his side's nerves after the visitors had briefly threatened to pile more misery upon Benitez.
Ramires put Chelsea in front in the 23rd minute and Eden Hazard returned from his ball boy suspension when he struck a low right-foot shot to increase the home side's lead after 56 minutes.
But Wigan reduced the deficit when Shaun Maloney scored from a tight angle on 58 minutes, and the Latics threatened before Lampard intervened to effectively seal the three points.
The home side gave the final score a slightly lop-sided look when late substitute Marko Marin headed his first goal for the club in injury-time.
The result lifted Chelsea back to third after Tottenham had earlier replaced them with a 2-1 victory over Newcastle at White Hart Lane.
Gareth Bale beat Tim Krul with a 25-yard free-kick to open the scoring for the Londoners and he then sealed the win with a superb break-away goal that ended with him slotting the ball between the Newcastle goalkeeper's legs.
Newcastle's goal came from Yoan Gouffran, who was later carried off on a stretcher with a serious-looking leg injury.
Arsenal goalkeeper Wojciech Szczesny produced some late heroics as the 10-man Gunners were forced to cling on for a 1-0 win over Sunderland at the Stadium of Light.
Arsene Wenger's men played the last half-hour with 10 men following Carl Jenkinson's sending-off for a second bookable offence.
Santi Cazorla made the decisive breakthrough in the 35th minute with a low shot past Simon Mignolet, who had earlier saved well from Aaron Ramsey.
Theo Walcott hit the post early in the second half but Sunderland finished in style with both Steven Fletcher and Adam Johnson denied late on by superb saves from Szczesny.
Rock-bottom QPR sunk closer to relegation after a dismal 4-1 defeat at Swansea.
Michu set the Swans on their way to victory with his eighth minute opener and Angel Rangel increased the home side's lead from close-range in the 18th minute.
Despite substitute Bobby Zamora briefly reducing the deficit, Pablo Hernandez restored Swansea's two-goal cushion on 50 minutes before Michu slid home his 15th league goal of the season to seal an easy win.
Fulham and Norwich played out a lacklustre goalless draw at Carrow Road, but the result gave both a valuable point to help them inch further away from the relegation zone.
Southampton 3-1 Manchester City
Chelsea 4-1 Wigan
Sunderland 0-1 Arsenal
Tottenham 2-1 Newcastle
Swansea 4-1 QPR
Stoke 2-1 Reading
Norwich 0-0 Fulham