Inter Milan crashed to their first defeat of the Serie A season on Wednesday, going down 2-1 at home to Sassuolo.
Inter went into the game with a perfect record of five wins in five and looked in control at 1-0 ahead thanks to a Denzel Dumfries goal on the stroke of half-time at the San Siro.
Sassuolo levelled in the 54th minute when Nedim Bajrami scored with a long-range effort which caught out goalkeeper Yann Sommer.
Domenico Berardi hit the winner 10 minutes later as Sassuolo claimed all three points to follow up last week's win over Juventus.
Inter remain top of the table on goal difference ahead of AC Milan who earlier defeated Cagliari 3-1.
