Chelsea were left stunned at White Hart Lane this evening as Tottenham Hotspur produced one of the performances of the season, claiming a 5-3 win at the expense of their rivals.
Jose Mourinho named the strongest squad available to him ahead of the encounter in north London, but it appeared that some perhaps celebrated to excess on New Year's Eve with this display.
The Blues weren't awful, but Spurs were simply better in all aspects. That didn't look likely in the opening 20 minutes, with the visitors looking unstoppable going forward and grabbing the lead through Diego Costa.
Harry Kane equalised when he was given too much time and space on the edge of the box though, and Danny Rose put Tottenham Hotspur ahead after Nacer Chadli's effort came back off the post.
That was on 44 minutes, but their was still time for Andros Townsend to make it 3-1 from the penalty spot before the break, capitalising after Gary Cahill cleaned out Kane in the box.
Things got even worse in the early stages of the second period when Kane spun and fired beyond Thibaut Courtois, before Eden Hazard pulled one back after a smart one-two with Cesc Fabregas.
Cesar Azpilicueta then went close to making it 4-3 but his effort was denied by Hugo Lloris, and Chadli made the Blues pay when his deflected effort found the corner. John Terry's late tap-in was nothing more than a consolation.
It all means Chelsea are now level with Manchester City at the top of the Premier League table, and the pair can't be separated by either points or goal difference.
Hazard stands alone
The way the Blues lost this game will be a particular concern to Mourinho, and a number of players failed to impress. Hazard looked lively throughout, but his performance wasn't matched by others. Defence looked particularly vulnerable, with Cahill and Terry exposed at regular intervals.
With a break in Premier League matches and the FA Cup up next, 'the Special One' might look to try something different against Watford - this was a result that is likely to lead to change.
But just how bad were some of the Chelsea players at White Hart Lane? Check out the GiveMeSport ratings below...
Chelsea Player Ratings
Thibaut Courtois - 6
Considering the Belgian conceded five goals, he didn't do much wrong and had little or no chance with any of the goals.
Branislav Ivanovic - 5
Gary Cahill - 3
A shocking display from start to finish, and could be in trouble post-match after a naughty looking incident with Harry Kane.
John Terry - 4
Cesar Azpilicueta - 6
Nemanja Matic - 5
Cesc Fabregas - 6
Willian - 4
Hugely disappointing and rarely influenced the game. Hooked over for Salah.
Oscar - 5
Eden Hazard - 7
Easily the Blues' best player on the day, looking lively going forward and creating chances. Lacked support on this occasion.
Diego Costa - 6