Milan - Cristiano Ronaldo scored his first goals for Juventus with his double inspiring a 2-1 win over Sassuolo but team-mate Douglas Costa disgraced himself for spitting in a rival's face, as the seven-time reigning champions opened up a gap at the top of the Italian league table as the only unbeaten team in four games.
Here are five things we learned from Serie A this weekend:
Ronaldo reaches 400-goal mark
Portuguese star Ronaldo set another mark with his double bringing his tally of league goals to 400 to join four other players who have achieved the feat in top European football.
The 33-year-old added to his three goals for Sporting Lisbon, 84 with Manchester United and 311 for Real Madrid in a total of 517 league matches.
The five-time Ballon d'Or winner becomes the first player since Germany's Uwe Seeler to hit the mark - Seeler scored 406 in the 1970s.
Czech-Austrian footballer Josef Bican leads the way (518) followed by Hungarian Ferenc Puskas (514) and Scotland's Jimmy McGrory (410).
Higuain also off the mark
Gonzalo Higuain also scored his first goal for AC Milan since his loan move from Juventus, to salvage a point in a 1-1 draw at Cagliari.
The Argentine pounced in the second half, to score his seventh goal in eight games against Cagliari, and 112th in Serie A, coming close to a second from close range.
"Gonzalo's goal was important, it can help him psychologically," said midfielder Franck Kessie.
"He keeps the ball and helps the team move up," said coach Gennaro Gattuso, adding: "We played an embarrassing first 20 minutes."
Joao Pedro got the first goal for Cagliari in his first game since returning from a six-month doping ban.
Roma lack 'killer instinct'
Roma coach Eusebio Di Francesco lamented his side's lack of killer instinct after early goals from Stephan El Shaarawy and Bryan Cristante appeared to put Roma in control, only to fall 2-2 to bottom side Chievo.
Roma have just five points from four games in which they have conceded seven goals.
"We lacked that killer instinct. We can't do any of that in Madrid," he added ahead of their midweek trip to Champions League holders Real Madrid.
Icardi nightmare start
Inter captain Mauro Icardi's nightmare start to the season mirrors his team's who have not kicked off the season so badly for seven years with just four points from four games.
The Argentine was the joint top Serie A scorer last season with 29 goals.
But struggling with a muscular problem he has failed to find the net in the three games he has played so far.
On Tuesday, Inter return to the Champions League with a clash with Tottenham Hotspur at San Siro, which could prove crucial for the future of coach Luciano Spalletti.
Long road ahead for AC Milan
AC Milan great Paolo Maldini believes the "road is long" before AC Milan can challenge Juventus.
"We have been coming from two years with two sixth places and, consequently, the road is very long," said Maldini, who spent his entire 25-year playing career at AC Milan, before returning as their sporting strategy and development director.
"Honestly, comparing Milan to Juve is very premature now. We have the goal to get to the Champions League, to do well in the Europa League."