(CNN) -- Chelsea slumped to a 3-1 defeat against West Ham at Upton Park on Saturday to heap further pressure on interim manager Rafa Benitez.
Juan Mata gave the visitors the lead in the 13th minute, but three second half goals -- one a piece for Carlton Cole, Mohamed Diame and Modibo Maiga -- saw Chelsea crash to their third loss in seven Premier League matches.
Since replacing Roberto Di Matteo earlier this month, Benitez has picked up just two points from three league games and continues to incur the wrath of some Chelsea supporters who once again held up banners signifying their distaste for the Spaniard.
With 26 points from 15 games the Blues have now made their worst start to a Premier League season since Roman Abramovich took over at Stamford Bridge in 2003.
The win moves West Ham up to eighth place, four points behind their more glamorous West London rivals.
Meanwhile in north London, Arsenal went down to a similarly discomfiting defeat at the hands of Swansea City at the Emirates.
The game looked to be heading towards a draw before two late goals from Spanish striker Miguel Michu snatched all three points for Michael Laudrup's side.
The win extends the Welsh club's unbeaten league run to six matches and lifts them to seventh in the table with 20 points. Arsenal are now tenth.
Manchester United sealed a thrilling 4-3 win against Reading at the Madejski Stadium with all the goals coming in the first half.
Hal Robson-Kanu put the home side in front in the eighth minute before Anderson equalized five minutes later.
Wayne Rooney edged United ahead with a spot kick three minutes later only for Adam Le Fondre to restore parity in the 19th minute. Four minutes later, Reading were back in front again as Sean Morrison headed home from a corner.
Rooney levelled the scores again on the half-hour mark before Robin van Persie joined the party with a cool finish in the 34th minute to complete a breathless opening period.
A frenetic first half gave way to a more sober encounter after the break with both teams creating few clear-cut chances.
United's win -- their third in a row -- puts them on 36 points at the top of the table, three clear of reigning champions Manchester City who dropped precious points on Saturday, drawing 1-1 with Everton at the Etihad Stadium.
Marouanne Fellaini put David Moyes' team ahead in the 33 minute before Carlos Tevez equalized from the penalty spot 10 minutes later after Edin Dzeko had been brought down.
Everton's Merseyside rivals, Liverpool picked a valuable three points against Southampton at Anfield -- Daniel Agger scoring the only goal of the game two minutes before the break.
The win moves Brendan Rodgers' side up 11th with 19 points from 15 games.
Two goals from Jermain Defoe and one from Raniere Sandro earned Tottenham Hotspur a resounding 3-0 victory against Fulham at Craven Cottage.
The win lifts Spurs to fourth, level on points with both Chelsea and West Bromwich Albion -- Steve Clarke's men slumped to their second consecutive defeat losing 1-0 to Stoke City.
Harry Redknapp's second game in charge of Queen's Park Rangers saw the Premier League's bottom side pick up a point against Aston Villa.
Brett Holman gave the Villa the lead in the eighth minute before Scottish striker Jamie Mackie equalized ten minutes later before a stalemate ensued.
The result still leaves QPR rock bottom with six points while Villa are 16th with 14 points.