Juventus' bid for a first Serie A title in four years hit a stumbling block on Saturday after Empoli snatched a surprise 1-1 draw from their 10-man hosts.
Tommaso Baldanzi stunned Turin's Allianz Stadium in the 70th minute of a stodgy encounter with Scudetto pretenders Juve, who missed the chance to move four points clear of Inter Milan.
Instead the league lead for Juve stands at two, meaning that Inter, who have two games in hand, will reclaim top spot if they win at fifth-placed Fiorentina on Sunday.
Massimiliano Allegri's side had to play more than three quarters of the match a man down after Arkadiusz Milik was sent off in the 16th minute for a clumsy and dangerous foul on Alberto Cerri.
"We didn't lose shape after going down to 10, rather we kept trying to win the game... I'm disappointed for the boys," Allegri told DAZN.
Next weekend Juve, whose winning streak in league and cup ended at seven matches, travel to the San Siro for the so-called "Derby of Italy" with Inter after failing to put a proper cushion between them and their fiercest rivals.
"The Derby of Italy is always a great game, it's a brilliant match to play and the stadium will be full. We'll go there to put in a top performance and try to get a result," Allegri said.
"They're the best team in the league and favourites to win the title."
Juve thought they were on course to secure the points when Dusan Vlahovic poked them ahead four minutes after halftime following chaos at a corner.
That was the Serbia striker's sixth goal in all competitions for Juve since the turn of the year.
But it wasn't enough for the win as Baldanzi, who is rumoured to be leaving for Roma before the end of this transfer window, rolled home his low leveller through a sea of legs.
The draw failed pull Empoli out of the relegation zone as Davide Nicola's team are in 19th place on 17 points, a point behind Cagliari and Udinese who sit just above the relegation zone.
"I'd keep any player I can from this squad because they're showing me that they care and above that they have desire to improve," said Nicola of Baldanzi.
Udinese stayed within reach of Empoli after being beaten 2-0 at Atalanta, allowing their hosts to move into the Champions League places above Fiorentina.
MAIGNAN'S MLK HOMAGE
AC Milan summoned inspiration from American civil rights hero Martin Luther King to show solidarity with goalkeeper Mike Maignan, pausing play in a 2-2 home draw with Bologna in which Riccardo Orsolini snatched a point for the away side with a stoppage-time penalty.
The fixture was stopped in the 16th minute in honour of Maignan's shirt number while a famous King quote was displayed on the San Siro's big screens.
"Darkness cannot drive out darkness; only light can do that," read the message.
Fans held up their phone lights while warm applause spread across the stands at the stadium for Maignan, who was racially abused at Udinese last week, and highlighting their "resolute stand against discrimination".
Milan are seven points behind Juve after a draw with this season's surprise package, which will hurt all the more for Olivier Giroud and Theo Hernandez fluffing penalties in each half.
Ruben Loftus-Cheek levelled Joshua Zirkzee's opener for Bologna on the stroke of halftime not long after Giroud trickled a weak spot-kick into the hands of Lukasz Skorupski.
And after Hernandez smacked the post with his 74th-minute spot-kick and then prodded home an illegal goal on the rebound, Loftus-Cheek headed home in the 83rd minute what looked to be the winner.
But Filippo Terracciano daftly tugged Victor Kristiansen's shirt as he tried to slide home a teasing low cross and Orsolini drilled his penalty under the despairing Maignan.