Mauro Icardi misses penalty as Inter falls to Cagliari
Icardi had a fantastic start to the season, with six goals in seven matches, but angered a section of fans known as "Ultras" at Inter with comments in his autobiography, which the supporters called "lies" in a lengthy statement.
A threatening banner was also left outside Icardi's house.
"We'll talk about it tomorrow, calmly, with respect to the footballer and respect to the fans," Inter coach Frank De Boer said. "We have to find a solution because this situation is not good.
"It's the most difficult moment since I've been in Italy. It's not a question of bad luck. I didn't expect this defeat. In the first 70 minutes we controlled the match. Then, after scoring, we forgot to play. With respect to Cagliari, we have to win against teams like them. Today instead I saw a team which didn't want to win and I think it's a mental matter."
Melchiorri has now scored two goals in his only two Serie A matches after a difficult few years that saw him undergo brain surgery and also return from a serious knee injury.
Cagliari, which won the second division last season, moved above midtable Inter to seventh place.
AC Milan 3, Chievo Verona 1
The match in Verona was a fight for third spot in Serie A.
And two stunning strikes saw AC Milan's young team—which included two teenagers in the starting lineup—move level with second-place Roma, below the capital side on goal difference alone.
Next up is the visit of Serie A leader Juventus but Milan coach Vincenzo Montella played down talk of a title fight with the five-time defending champion.
"Talk of that doesn't belong to us because we have to keep a low profile," Montella said. "Last year Inter was top until January, it seemed as if it had already won the title and then we know how it ended.
"Our aim is to get back into Europe, it's been too long that this team, with all its talent, has been out of European competition. These lads need confidence and the results help the players express themselves better and increase self-awareness. The team has to always have this desire to aim to get back into Europe."
Juraj Kucka broke the deadlock on the stroke of halftime with an unstoppable effort into the top left corner from 25 yards.
M'Baye Niang doubled Milan's lead immediately after the break with another long-range shot, which flew into the far side of the net.
The 21-year-old celebrated his goal by holding up and kissing a shirt with Riccardo Montolivo's name on it. The Milan captain is sidelined for six months with another injury.
Chievo got back into the match in the 76th with a magnificent goal of its own, a free-kick from former Milan winger Valter Birsa.
Milan sealed the match with a slice of luck as Chievo defender Dario Dainelli tried to block Carlos Bacca's effort, which looked as if it was going wide, but only succeeded in turning it into his own net.
It was Chievo's first defeat at home since January.
Lazio 1, Bologna 1
Lazio could have moved second in Serie A. Instead it needed a controversial last-gasp penalty to rescue a point against Bologna.
Other matches
Both teams also hit the woodwork twice.