Swansea City's Pablo Hernandez struck a late equalizer as Chelsea rounded off another controversial week by losing its place at the top of the Premier League after a 1-1 draw on Saturday.
The Blues have been embroiled in the furor over referee Mark Clattenburg's alleged inappropriate comments to John Obi Mikel, but they looked set to claim the spoils when Victor Moses nodded in his first league goal for the club in the 61st minute.
Swansea looked like it would be made to pay for its inability to craft clear-cut chances during the first half, but Hernandez seized on Itay Shechter's pass to fire low beyond Petr Cech with three minutes remaining.
The Welsh side was bursting with confidence after their midweek Capital One Cup win at Anfield, and there was a swagger about the Swans' play during a first half they had the better of without really creating a meaningful chance.
Branislav Ivanovic, back from suspension, made a critical early intervention for the Blues to block Angel Rangel's pull back and deny Michu an effort on goal as Swansea started smartly.
Chelsea highlighted its threat at the other end as Leon Britton cleared off the line from Fernando Torres' near-post header, which narrowly evaded the incoming Gary Cahill.
Ashley Williams was fortunate to escape any sanction when he appeared to force Eden Hazard over in the box, before the former Lille man freed Torres, only for Williams to get back and make a timely intervention.
Roberto Di Matteo brought on Ramires for the anonymous Oriol Romeu at the break and there was a marked improvement in the visitors' play.
Hazard cut inside to get away a low shot that Gerhard Tremmel held well to his right, before Moses wasted a superb opportunity by heading over from Torres' cross.
Ashley Cole's excellent block denied Jonathan De Guzman at the other end as the game opened up, but Swansea fell behind just after the hour mark.
Tremmel had saved Hazard's free kick, but from the resulting corner Moses flicked Cahill's header in off the post.
Swansea pressed as Chelsea looked to preserve its advantage, and a deserved leveler finally came from Hernandez's placed effort before Danny Graham was denied a winner by Cahill's excellent block.
Di Matteo did not feel off-field events were a factor in his side's failure to win.
"I wouldn't read anything into what has happened in the last week and the result today," he said. "It is very difficult to win away from home in the Premier League This is our second away draw of the season -- we have won the rest of the games. It is disappointing not to have hung on to our lead but even when you are not brilliant, you need to get a result like that. It's a long season and it is going to stay very tight at the top."
In other Premier League games on Saturday, Tottenham is no longer fourth after Andre Villas-Boas' side was beaten 1-0 by Wigan at White Hart Lane. Wednesday's disappointing Capital One Cup exit at Norwich filtered into the north Londoners' weekend display, and they were booed off after Ben Watson's winner.
The first half was surprisingly dominated by the visitors, who should have taken the lead through Shaun Maloney when the former Celtic man broke the offside trap. That pattern continued into the second half and Wigan grabbed a deserved opener when Brad Friedel buckled under pressure at a set-piece, allowing Watson to poke home.
Villas-Boas drew the wrath of the home crowd by withdrawing Jermain Defoe for Emmanuel Adebayor, but it was Wigan who nearly scored again through a Maynor Figueroa free-kick as they held on for victory.
"It was maybe our worst performance of the season," said Villas-Boas. "We didn't manage to keep the ball or pass well. We couldn't recognise ourselves today. Wigan were superior. Our chances weren't clear cut. There are various reasons why we played like this. The opponents were sharp and aggressive. We kept making mistakes. We played more with the heart rather than the head."
Everton was stunned after Steve Sidwell fired a late equalizer that allowed Fulham to escape with a point from a 2-2 draw. Apart from their seventh-minute opener on a Tim Howard own goal and Sidwell's 90th-minute strike, Martin Jol's side was over-run by the rampaging visitors.
Marouane Fellaini scored twice for Everton and nearly had more.
Gabriel Agbonlahor's first league goal of the season was enough to see off shot-shy Sunderland as Aston Villa won 1-0 to ruin former boss Martin O'Neill's day.
The striker fired home from close range 12 minutes after the break to claim just a second league victory of the season for the midlanders on an afternoon when the Black Cats mustered only a single notable effort on target, and that six minutes from time.
Bradley Johnson headed in the only goal as Norwich continued its revival with a hard-earned 1-0 win over Stoke at Carrow Road.
The Canaries are unbeaten in four games across all competitions following the international break.