For the first in 67 years, the big quartet of AC Milan, AS Roma, Juventus and Inter Milan lost a game on the same day.
The last time it occurred was in 1955.
Matchday 7 started with Inter Milan losing 3-1 away at the (Dacia Arena) Fruili stadium to Udinese despite taking a fifth minute lead through Nicolo Barella.
Then followed struggling Juventus who capitulated at the U-Power Stadium to their host, Monza, losing 1-0.
If Inter could be forgiven for losing to a team that is in form and in the top half of the table before the game, the Old Lady had no justification to lose to Monza, a team at the bottom of the log before the start of the game.
At the Stadio Olimpico in Rome, AS Roma did the playing and gaffer Jose Mourinho got a red card as the host lost to visiting Atalanta by a iorgio Scalvini’s 35th minute goal.
Then followed the match of the weekend at the San Siro where AC Milan lost their unbeaten Serie A run to Napoli.
Second half goals from Matteo Politano and Giovanni Simeone gave Napoli a statement win at the San Siro, one managed without injured star striker Victor Osimhen and suspended coach Luciano Spalletti not on the bench.
The Partenopei are now the table leaders with Atalanta, both at 17 points.