Jose Mourinho suffered only his second ever Serie A home defeat as former club Inter Milan strolled to a 3-0 win over Roma at the Stadio Olimpico.
This was Mourinho's first meeting with Inter since winning the treble there in 2010.
But it was not a night to remember for the Portuguese as Roma folded after Hakan Calhanoglu had scored direct from a corner.
Edin Dzeko added a second against his old club and Denzel Dumfries' diving header ended the contest before half-time.
Inter went second as city rivals AC Milan took top spot by dominating Salernitana for a comfortable 2-0 success at the San Siro.
On a day when injury-hit Milan lost defender Simon Kjaer for the rest of the season following knee surgery, Franck Kessie and Alexis Saelemaekers were on target inside the opening quarter.
Napoli started the day top of the pile but lost 3-2 at home to Atalanta.
Piotr Zelinski and Dries Mertens put Napoli ahead after Ruslan Malinovskyi's opener, but second-half goals from Merih Demiral and Remo Freuler gave Atalanta victory.
Real Madrid extended their lead at the top of La Liga to eight points by winning 2-0 at Real Sociedad.
Vinicius Junior put Real ahead two minutes after the restart and Luka Jovic's close-range header sealed the points.
Sevilla overcame Villarreal 1-0 with Lucas Ocampos heading a 15th-minute winner.
Xavi suffered his first defeat as Barcelona manager with Real Betis moving into third with a 1-0 victory at the Nou Camp.
Barcelona remain in seventh after Betis' 79th-minute winner from Juanmi, who finished coolly after being slipped in by former Barca forward Cristian Tello.
Defending champions Atletico Madrid slipped to a shock 2-1 home defeat to Mallorca.
Atletico led through Matheus Cunha's scuffed effort after 68 minutes, but Franco Russo levelled from a free-kick and Real Madrid loanee Takefusa Kubo raced clear in added time for the winner.
Robert Lewandowski scored twice as Bayern Munich moved four points clear of Borussia Dortmund with a come-from-behind 3-2 triumph in a pulsating Der Klassiker.
Julian Brandt put Dortmund ahead after five minutes, but Lewandowski quickly levelled and Kingsley Coman gave Bayern a half-time lead.
Erling Haaland equalised with a superbly curled effort just after the break, but Lewandowski converted his 16th goal of the campaign - and his 40th of the calendar year - from the penalty spot 13 minutes from time.
Dortmund coach Marco Rose was sent off with a second booking for dissent following the penalty decision.
Patrik Schick scored four second-half goals as third-placed Bayer Leverkusen crushed rock bottom Greuther Furth 7-1 for their biggest ever Bundesliga home victory.
Amine Adli and Edmond Tapsoba put Leverkusen 2-0 ahead inside 17 minutes before Jeremie Dudziak reduced the deficit.
Ecuadorian teenager Piero Hincapie restored Leverkusen's two-goal advantage on the stroke of half-time and the second period was the Schick show as the Czech Republic striker scored four times between the 49th and 76th minutes.
Hoffenheim came from behind to beat Eintracht Frankfurt 3-2 and move into fourth spot.
Dennis Geiger, Georginio Rutter and Diadie Samassekou were all on target for Hoffenheim, with Rafael Borre - who had opened the scoring after 15 minutes - and Goncalo Paciencia replying for Eintracht.
Mainz leapfrogged Wolfsburg into seventh with a 3-0 win. Jonathan Burkardt and Anton Stach struck inside the opening four minutes and Maxence Lacroix headed into his own net late on.
Georginio Wijnaldum's first league goal of the season saved leaders Paris St Germain in a 1-1 draw at Lens.
Seko Fofana put Lens ahead just after the hour mark but Wijnaldum struck in the second minute of stoppage time to put PSG 13 points clear.
Second-placed Marseille were upset 2-1 at home by Brest with Romain Faivre and Franck Honorat wiping out Gerson's opener.
Jonathan David and a late Jimmy Giraudon own goal gave Lille a 2-1 win over Troyes, who had led after six minutes through Tristan Dingome.