Champions Inter Milan lost ground in the Serie A title race after a shock home defeat to Sassuolo.
Simone Inzaghi went into Sunday’s fixture knowing AC Milan – league leaders by two points – had only drawn at Salernitana on Saturday.
But they were stunned when Giacomo Raspadori put Sassuolo ahead and Gianluca Scamacca doubled the lead.
Milan Skriniar, Ivan Perisic, Edin Dzeko and Lautaro Martinez squandered chances as Inter stayed second.
Even when they did find the net, four minutes into added time, Stefan de Vrij’s effort was ruled out by VAR.
Inzaghi’s side still have a game in hand on AC Milan and a win would give them top spot.
But this was a wasted opportunity and owed to a slack start and their failure to make 17 shots at goal count for more.
It continues a worrying run of form for Inter who were beaten at home by Liverpool in the Champions League on Wednesday and have now won just one of their last five games in Serie A.
Sassuolo in contrast ended a four-game winless run in the league and now sit 11th.
Forward Domenico Berardi was on hand to create their opener and he is now the only player in double figures for both goals and assists in Serie A this season.