In an atmosphere befitting the man, hundreds of Milan fans turned out to welcome the Italy international to the club he supported as a boy
- with scenes even turning ugly overnight as police battled fans surrounding the restaurant where he ate last night.
After the deal was finally sealed this morning, Balotelli joined his new team-mates in training this afternoon with the Milan website reporting that he scored in a friendly match against Darfo Boario.
It will be down to more serious business on Sunday evening with Milan needing a win over Udinese to keep the pressure on rivals Inter in the battle for Europe.
Balotelli's former club have been busy in the transfer market too, with Zdravko Kuzmanovic and Ezequiel Schelotto drafted in on deadline day and Mateo Kovacic also expected to join.
Their chance to make their debut will come on Sunday afternoon when Inter travel to basement-boys Siena, where victory would carry Inter six points clear of Milan, at least for a few hours.
Leaders Juventus travel to Siena defending a three-point advantage over Napoli, who will be happy to see the transfer window shut with nobody having tested their resolve to keep Edinson Cavani, who has declared himself happy at the club and eager to chase down Juve.
"We have a big chance [to win the title] and we cannot ignore that," he told Gazzetta dello Sport. "The numbers show that the Scudetto is within our reach.
"We can go all the way and we will do our utmost to make it happen. Even more so than Juventus, we are very hungry for success, just like they were last term.
"We are incredibly motivated. The team is focused on the task at hand and we want to make this dream come true. We are showing that we have the determination to win the title."
They host a Catania side riding high in seventh place but sporting a rather poor away record, with only two wins from 10.
Lazio are just three points behind Napoli as they prepare to travel to relegation-threatened Genoa.
Roma coach Zdenek Zeman insists that third place is still within reach for his side but they have plenty to do to get there as they sit eighth, nine points behind their city rivals.
They can close that gap at least temporarily when they kick off the weekend's action at home to Cagliari tomorrow night.
Balotelli's arrival in Milan is likely to make Fiorentina's bid for European football more difficult to achieve, and they cannot afford a slip-up against a Parma side only five points behind them in the table.
Palermo were very active in the transfer window as they bid to escape the relegation zone, and coach Gian Piero Gasperini will have some tinkering to do to his side as they prepare to face Atalanta.
Elsewhere, Sampdoria travel to Torino and Pescara host Bologna.