Two of the top Serie A coaches are already feeling the pressure after Juventus and Inter Milan both lost on a miserable day for some of the traditional greats of Italian soccer.
It was the first time since February 1955 that Juventus, Inter, AC Milan and Roma have lost on the same day in the Italian league.
Promoted Monza probably didn't expect their first-ever Serie A win to come against Juventus but they managed to beat Massimiliano Allegri's side 1-0. Juve played most of the match with 10 men following Angel Di Maria's red card.
"I wish to apologize to everyone for that inappropriate reaction I had on the pitch," he posted on social media.
"Having left the team a man down in such a difficult moment of the season made us lose the game.
"It is purely my fault that we lost. I am so very sorry. I am a professional, but also a human being who makes mistakes and can recognize them."
Simone Inzaghi is also under pressure after his Inter side were beaten 3-1 at Udinese for their third league loss of the season in seven rounds.
Napoli remain top after inflicting a first defeat of the season on defending champions AC Milan. Napoli won 2-1 and are one of the two remaining unbeaten teams along with Atalanta, who won 1-0 at Roma.
Juventus went to winless Monza, owned by former Milan owner and Italian prime minister Silvio Berlusconi, who had conceded 14 goals in their six games.
Home fans went wild in the 74th minute when Patrick Ciurria whipped in a cross from the right and Christian Lund Gytkjaer volleyed in at the near post.
At the San Siro, Matteo Politano converted a 55th-minute penalty before Olivier Giroud levelled in the 69th and Giovanni Simeone headed in the winner 12 minutes from time.
Udinese continued their surprising start to the season by recording a fifth straight win to go third.
Nicolo Barella curled in a fantastic fifth-minute free kick to get Inter off to the perfect start but Udinese levelled when Roberto Pereyra's free kick deflected in off Milan Skriniar.
Jaka Bijol headed in a corner with three minutes remaining and Tolgay Arslan made sure of the points in added time with a diving header.
Roma coach Jose Mourinho was sent off in the defeat to Atalanta.
Mourinho was shown a red card after going onto the field to remonstrate with the referee and had to be held back by a member of his staff.
Teenage defender Giorgio Scalvini scored the only goal of the match at the Stadio Olimpico in the 35th minute.
And Socceroos midfielder Ajdin Hrustic made his starting debut for Hellas Verona since his move from Eintracht Frankfurt in Germany. But the 26-year-old was substituted after 60 minutes in his side's 2-0 loss at Lazio.