Inter Milan’s Champions League qualification hopes were kept in check by a 3-1 defeat away to Sassuolo on Sunday when both sides finished with 10 men.
Sassuolo, claiming their first league victory over the Nerazzurri, moved up four places to eighth to sit two points ahead of Inter, who dropped one place to 12th at 23 points behind leaders Juventus.
Italy striker Simone Zaza opened the scoring for the hosts in spectacular fashion, firing past Samir Handanovic and into the top corner of the net in the 17th minute to send the Mapei Stadium wild with celebration.
Sassuolo doubled their lead on the half-hour when Nicola Sansone collected from a corner and fired an unstoppable shot from a difficult angle in off the underside of the crossbar.
Sassuolo took their foot off the pedal and Swiss international Xherdan Shaqiri spurned two chances to reduce arrears before Inter finally fought their way back into the game.
Mauro Icardi, who replaced Lukas Podolski just before the hour, pounced on a poor back pass by Francesco Magnanelli to round Andrea Consigli and fire into an empty net.
Tensions had already been high and they spilled over after the goal and then on the stroke of full-time when Sansone received a red card for following through on Shaqiri.
Inter were then reduced to 10 men moments later when Isaac Donkor was shown a second yellow card after a nudge on Zaza in the box which gave the hosts a penalty.
Berardi stepped up to beat Handanovic from the spot to seal a famous league victory for Sassuolo against an Inter side whose chances of finishing third this season now look desperately thin.