In the small break between the transfer window shutting and the Champions League group stage starting, Serie A frontloads its weekend schedule with last season's top four in action on Saturday.
Champions AC Milan face Inter at the San Siro after Juventus visit Fiorentina in the day's opening match.
Napoli conclude the evening at Lazio.
After nine seasons of Juventus domination, the Milan rivalry became decisive again in the last two season, as each club won a title and finished runners-up.
Inter did a lot of their big business early in the transfer window.
Milan were still stuffing stars in their Prada bag right up to Thursday's deadline, with Belgian midfielder Aster Vranckx joining from Wolfsburg and American full-back Sergino Dest coming in on loan from Barcelona.
Yet the biggest Serie A acquisition of the summer was AC Milan itself, bought on Wednesday by investment fund RedBird for a reported 1.2 billion euros (1.3 billion dollars).
In Europe, Milan travel to Salzburg on Tuesday. Inter have 24 hours longer to prepare and are at home against Bayern Munich.
Inter will likely be without star signing Romelu Lukaku, who missed Tuesday's win over Cremonese with a thigh injury.
Coach Simone Inzaghi made several unforced changes and indicated he will rotate again.
"We're going to have back-to-back games for a while now and it's not easy to recover all your energy," he said.
But he promised he would not take the derby lightly.
"It's an important game, both for us and our fans."
Juventus will have an eye on Tuesday's visit to Paris Saint-Germain.
In Serie A, Juve beat Spezia 2-0 on Wednesday with one of their marquee summer signings Arkadiusz Milik coming off the bench for the last five minutes and scoring.
"When everyone is fit we will be a good team," the Pole said after his debut.
Leandro Paredes, who joined on loan from next week's foe PSG earlier on Wednesday, could figure in Florence.
"A strong player, who has great technique," said Juve coach Massimiliano Allegri.
The early season pace-setters are in action later in the weekend. Roma visit mid-table Udinese on Sunday. The next evening Atalanta are at last-place Monza.
One to watch: Fiorentina fans
"These people are professional trolls," said Napoli coach Luciano Spalletti after a finger-wagging dispute with home fans as his team drew in Florence last Sunday.
Many fans are rude, but the unusually narrow Artemio-Franchi stadium puts supporters only inches away from the visiting dugout.
"Shall we talk about the rudeness of the Fiorentina fans who are behind the bench?" Spalletti asked on broadcaster DAZN.
"There are some back there who offend you from start to finish. They have children sitting right next to them and I cannot even repeat what they said.
"They start insulting your mum constantly. My mum is 90 years old. Leave her alone."
It might be a local difference. Florence is the capital of Tuscany. Spalletti is a Tuscan, from nearby Certaldo. So is Saturday's away bench guest, Allegri, who is from Livorno, a little more distant on the Tyrrhenian coast.
Home fans might also be encouraged because Fiorentina beat visiting Juventus in the final game of last season.
6: Divock Origi, who should be fit to return for AC Milan against Inter, acquired a reputation as a derby specialist by scoring six of his 22 Premier League goals for Liverpool against neighbours Everton.
Fixtures (all times GMT)
Fiorentina v Juventus (1300), AC Milan v Inter Milan (1600), Lazio v Napoli (1845)
Cremonese v Sassuolo (1030), Spezia v Bologna (1300), Verona v Sampdoria (1600), Udinese v Roma (1845)
Monza v Atalanta (1630), Salernitana v Empoli (1630), Torino v Lecce (1845)