Chelsea took sole possession of first place in the Premier League table after they beat Newcastle United 2-0 on Saturday and Manchester City drew 1-1 at Everton.
Chelsea began the day dead-level with City, but with the defending champions dropping points for only the second time in 10 matches, Jose Mourinho's side moved two points clear.
Chelsea took the lead in the 41st minute when Oscar tapped in Branislav Ivanovic's cross after Willian took a quick corner and they went on to add a delightfully constructed second goal just before the hour, with Diego Costa gathering a clever back-heel from Oscar and drilling in his 15th goal of the campaign.
At Goodison Park, City went ahead in the 74th minute when Fernandinho helped a shot from David Silva over the line with his head, but Steven Naismith equalised four minutes later, glancing home a cross from Leighton Baines.
Tottenham Hotspur can move into the top four if they win at Crystal Palace later on Saturday, with third-place Manchester United and fourth-place Southampton facing off at Old Trafford on Sunday.
West Ham United spurned a chance to climb to fifth place after being held to a 1-1 draw at Swansea City. Andy Carroll put West Ham ahead in the 43rd minute with a fine effort, chesting down a high ball and then dancing across the box before slamming a left-foot shot into the top-right corner from 15 yards.
But Swansea equalised in the 74th minute when a header from France striker Bafetimbi Gomis hit the post, struck West Ham midfielder Mark Noble and rebounded into the net for an own goal.
Burnley climbed out of the relegation zone and dragged Queens Park Rangers into the bottom three with a 2-1 home win over Harry Redknapp's side. Scott Arfield's opener was cancelled out by a penalty from former Burnley striker Charlie Austin, but Danny Ings gave the hosts victory in the 37th minute by rolling the ball past Rob Green after a neat piece of control.
Bottom club Leicester City closed to within two points of safety by winning 1-0 at home to Aston Villa, with Paul Konchesky slamming in the only goal in first-half stoppage time.
In his first league game as manager, Tony Pulis saw West Bromwich Albion climb to 14th after Saido Berahino's 78th-minute goal secured a 1-0 home win over Hull City.
Lazar Markovic scored the only goal as improving Liverpool provisionally closed to within four points of the Premier League's top four by winning 1-0 at Sunderland on Saturday.
At a gusty Stadium of Light, the 20-year-old Serbia winger's ninth-minute strike — his first Premier League goal — enabled Liverpool to extend their unbeaten run to five league games.
Gus Poyet's Sunderland, who had Liam Bridcutt sent off for two bookable offences, remain three points above the relegation zone with only one win from their last 11 games.
Having earlier seen a penalty appeal waved away after tumbling under a challenge from Wes Brown, Markovic put Liverpool ahead when he gathered a pass from Fabio Borini and prodded the ball between Costel Pantilimon's legs.
Markovic then hit the bar with a spectacular, improvised scissors kick as Liverpool dominated, while former Sunderland loanee Borini rounded Pantilimon, only to find the side-netting.
The visitors lost Steven Gerrard at half-time, with Dejan Lovren coming on, but their position was strengthened in the 49th minute when Bridcutt was shown a second yellow card for impeding Emre Can.
Moments later, Adam Johnson left the Liverpool crossbar shuddering with a swerving drive from distance, but Brendan Rodgers's side finished strongly, with Pantilimon saving from Mario Balotelli and Philippe Coutinho.
Co-leaders Chelsea and Manchester City are both in action later on Saturday, with Chelsea hosting managerless Newcastle United and City visiting out-of-form Everton.
The two pace-setters were left dead-level on points, goal difference, goals scored and goals conceded after the New Year's Day fixtures.
Tottenham Hotspur can move into the top four if they win at Crystal Palace, with third-place Manchester United and fourth-place Southampton facing off at Old Trafford on Sunday.
Barcelona coach Luis Enrique claimed he hadn’t been affected by rumours that he could become the latest high-profile exit from the Camp Nou should his side fail to beat Atletico Madrid on Sunday.
However, the 44-year-old said he would step down after just seven months in the job if he felt he no longer had the backing of his players.
“There are so many reports, some of them badly intentioned,” he said on Saturday.
“I won’t get involved in this dangerous game. What I can guarantee is that the day I see that my players don’t follow me, I will leave.”
A destabilising week for the Catalan giants began with a shock 1-0 defeat to Real Sociedad last weekend after Luis Enrique had left nearly Dhs 1.3 billion (€300m, $355m, £234m) of talent, including Lionel Messi and Neymar, on the bench.
The unrest at the Camp Nou kicked into overdrive on Monday when sporting director Andoni Zubizarreta was sacked, his assistant and club legend Carles Puyol resigned and Messi then missed an open training session with the club’s fans.
The Argentine sparked transfer rumours by then following Chelsea on the social networking site Instagram, while reports emerged that his relationship with Luis Enrique is at breaking point.
On Wednesday, club president Josep Maria Bartomeu called early elections for the end of the season in response to the increasing pressure on his position.
On the field there was some respite as Barca eased towards the quarter-finals of the Copa del Rey with a 5-0 thrashing of Elche on Thursday. However, the coach’s name was booed by the home fans as they showed their support for Messi.
“I continue to be concentrated and motivated. There is nothing that will distract me,” Luis Enrique added.
“All that I see behind closed doors motivates me. The players and the technical team remain on the fringes of all that. We are used to it.
“Tomorrow we are playing for three important points, but three points all the same. I feel the same as on my first day.”
Barca and Atletico are tied on 38 points in second place, one point adrift of La Liga leaders Real Madrid, who also have a game in hand.
However, by contrast to the crisis enveloping Barcelona, Atletico arrive in the Catalan capital full of confidence after beating Real Madrid for the third time this season 2-0 in the Cup on Wednesday as Fernando Torres made his first appearance since returning to the Vicente Calderon.
Diego Simeone’s side were unbeaten in six meetings against Barca last season as they sealed La Liga at the Camp Nou in May and also dumped Gerardo Martino’s men out of the Champions League.
— FC Barcelona (@FCBarcelona) January 10, 2015
And Luis Enrique expects another serious test this weekend.
“Atletico don’t look vulnerable. They have added players and they all defend very well.
“We don’t have that luck. I expect it will be a game like the ones last season, although with a different result.
“We need to attack and defend well because it will be a difficult game.”