Wilfried Zaha rocked Chelsea as Crystal Palace breathed new life into the Premier League title race with a stunning 2-1 win over the leaders at Stamford Bridge on Saturday.
In a frantic start, the Ivory Coast winger cancelled out Cesc Fabregas's opener and teed up Christian Benteke for the winner as Chelsea lost at home for the first time since September 16.
Second-place Tottenham Hotspur took advantage by winning 2-0 at Burnley to trim Chelsea's lead to seven points.
"I'm stunned. They're top of the league. No-one would expect us to come here and do that," said Zaha, whose side have won four games in a row.
"We know there's talent here. We just needed to work together. Everyone is seeing it now."
Liverpool closed to within 10 points of Chelsea, albeit having played a game more, after sinking Everton 3-1 in the Merseyside derby.
But Manchester United lost ground in the race for top-four places following a frustrating 0-0 draw at home to West Bromwich Albion.
Zaha's headline-grabbing display against Chelsea followed a week of headlines about his decision to switch international allegiances from England to Ivory Coast last year.
His side fell behind in the fifth minute when Eden Hazard crossed from the left for Fabregas to score at the near post.
But Zaha levelled matters in the ninth minute, drilling home through a posse of defenders, and two minutes after his pass freed Benteke to dink a cocky finish over Thibaut Courtois.
Despite losing defenders James Tomkins and Scott Dann -- Tomkins's replacement -- to injury, Sam Allardyce's patched-up Palace side gallantly held on to stay four points clear of the bottom three.
"This is football. We must accept this result," said Chelsea manager Antonio Conte.
"In every game in England, anything can happen. The league is so strong."
Tottenham kept their title hopes flickering after Eric Dier scored from close range and Son Heung-Min converted a cross from Dele Alli in the second half at Burnley.
However, victory came at the cost of injuries to midfielders Victor Wanyama and Harry Winks, who was taken to hospital with a potentially serious ankle injury.
Philippe Coutinho scored a dazzling goal and made another for Divock Origi as Liverpool overcame Everton at Anfield.
Manchester United now lie four points off the Champions League positions in fifth place after being held to an eighth draw of the season at Old Trafford by West Brom. And Leicester City's resurgence continued with a 2-0 home win over Stoke City that gave Craig Shakespeare a fifth successive victory since succeeding Claudio Ranieri as manager.