LONDON (AFP) - Chelsea dropped points for only the third time this season as the Premier League leaders were held to a 0-0 draw at Sunderland on Saturday.
Jose Mourinho's side had swept to the top of the table with 10 wins from their 12 matches and only Manchester City and Manchester United had avoided defeat against the Blues in domestic action.
But Chelsea were unable to break down dogged Sunderland, who held the Blues without a goal for the first time in 20 matches in all competitions this season.
The west Londoners are now seven points clear of second placed Southampton, who host champions City on Sunday.
Chelsea winger Willian almost opened the scoring with a fiercely struck low shot that rebounded off a post.
Yet Sunderland were making it tough for Mourinho's men and Santiago Vergini fired against the crossbar from 10 yards.
A tetchy encounter got even more heated when Chelsea striker Diego Costa escaped with a booking rather than a red card for an elbow on Sunderland defender Wes Brown.
West Ham leapfrogged Newcastle into fifth place with a 1-0 win at Upton Park.
Newcastle had climbed into the top five on the back of five successive league victories, but they fell behind in the 56th minute when Hammers left-back Aaron Cresswell turned in Cheikhou Kouyate's miscued shot.
The Magpies' hopes of an equaliser were wrecked when midfielder Moussa Sissoko was sent off for earning two bookings in the space of 46 seconds in the second half.
QPR moved off the bottom of the table at the expense of fellow-strugglers Leicester, who slipped to 20th place after their 3-2 defeat at Loftus Road.
Burnley rescued a 1-1 draw against relegation rivals Aston Villa at Turf Moor, while Swansea and Crystal Palace drew 1-1 at the Liberty Stadium.