Roma's lead at the top of Serie A was cut as their mini stumble continued after a goal four minutes into injury-time by Domenico Berardi saw struggling Sassuolo claim a 1-1 draw at the Stadio Olimpico.
Rudi Garcia's side had seen their perfect run come to an end last weekend with a draw at Torino but Sunday's game against their lowly visitors appeared to offer a great chance to immediately return to winning ways.
An own goal by Alessandro Longhi after 19 minutes put the hosts ahead and they were completely dominant.
However, they failed to capitalise on that and were made to pay in injury-time as they conceded for just the third time this season.
While Roma remained top, it meant their lead was cut to one point after second-placed Juventus crushed fellow title chasers Napoli 3-0 in Turin.
Juve claimed the win with goals from Fernando Llorente, Andrea Pirlo and Paul Pogba.
Only the late dismissal of Angelo Ogbonna soured an otherwise memorable day for Antonio Conte's side, who have now won eight of their past nine league games.
Two goals from Giuseppe Rossi helped move Fiorentina up to fifth with a 2-1 win over Sampdoria.
Rossi opened the scoring with a penalty after just nine minutes and doubled the lead 10 minutes later with a long-range effort.
Manolo Gabbiadini got a goal back for the visitors 16 minutes from the end but they could not find an equaliser despite having the best of the closing stages.
AC Milan's worst start to a season since 1981 continued as they were held to a 0-0 draw at Chievo which further increases the pressure on coach Massimiliano Allegri.
It could have been even worse for the Rossoneri as Chievo saw a goal disallowed for offside midway through the second half, although Robinho hit the post on a frustrating afternoon for Milan at the Stadio Marc'Antonio Bentegodi.
Both sides ended the game with 10 men, Riccardo Montolivo followed down the tunnel by Sergio Pellissier towards the end of the match.
Genoa picked up their fourth win out of six games since Gian Piero Gasperini took over as coach with a 2-0 success over Hellas Verona.
The Rossoblu's third win in a row, secured by goals from Daniele Portanova and Juraj Kucka in the first half, lifted them to within five points of their opponents and into a much healthier position than the one they found themselves in when Gasperini took charge.
Balde Keita made his entrance into Serie A with an inspiring performance, and a goal, although it was not enough for Lazio to take all three points as they recorded a 1-1 draw at Parma.
The 18-year-old gave the Biancoceleste the lead early in the second half after tearing the Parma defence apart in the first 45 minutes, but an equaliser from Alessandro Lucarelli soon after earned the home team a point.
The point may not be enough for Lazio's under-pressure coach Vladimir Petkovic, however, with his side still languishing behind the top six.
A late goal from Daniele Conti saw Cagliari snatch a 2-1 win at home to Torino and end a run of three successive league defeats.
The midfielder had also given the hosts a first-half lead but a draw seemed the most likely result following Ciro Immobile's equaliser, until Conti struck again two minutes from time.
It was only the second win in 11 matches for Cagliari but lifts them above Torino - who remain without a victory since September 22 - in the standings.
Marko Livaja grabbed a late winner as Atalanta saw off the challenge of Bologna at the Stadio Atleti Azzurri d'Italia.
The Croatian forward scored with practically the last kick of the game to seal a 2-1 win for Stefano Colantuono's men after Davide Brivio's goal had been wiped out immediately by Rolando Bianchi.
The win lifts the Nerazzurri three points clear of AC Milan in mid-table and leaves Bologna just a point above the drop zone.