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.
"It was a difficult match. Only one team tried to win from the beginning, the other team didn't. They defended a lot and they defended well," said Mourinho, whose side remain unbeaten this season.
"We were a bit tired towards the end and we left a bit of space. But I've got nothing negative to say about my team."
Danny Welbeck returned from injury to maintain Arsenal's recent revival as the England striker sealed a 1-0 win at West Bromwich Albion.
Arsene Wenger's Arsenal had been under pressure after successive Premier League defeats condemned them to their worst start for 30 years, but a midweek victory over Borussia Dortmund, which booked their place in the last 16 of the Champions League, had lifted spirits at the north London club.
Welbeck missed that win due to hamstring and knee problems, but he was back at the Hawthorns to net his sixth goal for Arsenal from Santi Cazorla's 60th minute cross, giving the Gunners only their fifth league victory of the season.
Despite the win, some Arsenal fans held up a banner at full-time calling for Wenger to quit.
Asked if he was affected by the protest, Wenger said: "I don't want to comment on that. I try to do my best for this club that I love.
"It's easier to deal with the upwards than the downwards, but you cannot be a manager and have only one side."
Liverpool ended their three-match losing streak as Glen Johnson's late goal clinched a hard-fought 1-0 success against Stoke at Anfield.
Reds captain Steven Gerrard was dropped to the bench on the 16th anniversary of his Liverpool debut and Brendan Rodgers' side were lacklustre without him.
But Gerrard came on for the final 16 minutes and Johnson popped up with the winner in the 85th minute after Rickie Lambert's header hit the bar.
"The players were absolutely incredible. We fully deserved it and to keep a clean sheet against a very good side was pleasing," Rodgers said.
Robin van Persie scored only his fourth goal for Manchester United this season as the hosts cruised to a 3-0 win over Hull at Old Trafford.
United's injury problems continued early in the first half when Argentina midfielder Angel di Maria was forced to come off.
But Louis van Gaal's side took the lead in the 16th minute as video technology showed Chris Smalling's scrambled effort had crossed the line to give the much-maligned defender his first goal since December 2013.
United captain Wayne Rooney got the second goal, sweeping home from 20 yards in the 42nd minute, and van Persie netted in the 66th minute to seal his fourth-placed team's third successive win.
"It was the best match of our season. What pleased me most was the way we dominated the game from the first minute to the last minute," van Gaal said.
"Di Maria is out of Tuesday's game against Stoke. But we will have to wait and see how bad it is."
West Ham leapfrogged Newcastle into fifth place with a 1-0 win at Upton Park.
Newcastle fell behind in the 56th minute when Hammers left-back Aaron Cresswell netted and the visitors also had midfielder Moussa Sissoko sent off for 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.