Champions Milan bounced back from going behind with less than two minutes on the clock to claim the three points thanks to two goals from Ante Rebic, a Theo Hernando penalty and a strike from Brahim Diaz.
The margin of defeat was harsh on Udinese who acquitted themselves well in front of a raucous home crowd at the San Siro.
However three points and four goals were the perfect way for Milan to kick-off what is likely to be a tight title tussle in Italy, with no clear favourite ahead of the start of the campaign.
“We can do better, there were a lot of positives but and other things on which we can improve but that normal for this period of the season,” said Pioli to DAZN.
Fans at a packed San Siro roared “we are the champions” as the team came out on a balmy summer’s evening in Milan, but they were soon stunned into silence when Rodrigo Becao met Gerard Deulofeu’s corner with a header which squeezed past Mike Maignan.
Milan responded and were ahead with less than a quarter of a hour gone after a long VAR check on a clash between Davide Calabria and Udinese’s Brandon Soppy led to Hernandez smashing in his 12th-minute spot-kick. Rebic swept home the hosts’ second three minutes later.
Udinese were livid at the decision to award Milan’s penalty, described as “without any logic” by the club’s technical director Pierpaolo Marino.
A hugely entertaining first half ended with the Milan fans again wondering what was going on thanks to Adam Masina, whose diving header in the fourth minute of added time levelled the scores in spectacular fashion.
Masina then calmed the home side’s nerves when he handed Diaz a tap-in to put Milan back ahead, unwittingly nodding Hernandez’s cross into the Spaniard’s path.
Diaz was at the heart of things again in the 68th minute, pressuring Roberto Pereyra in the Udinese area before nicking the ball and rolling back a low pass which Rebic stretched to push in the fourth which sealed the win.
– Dumfries steals the show –
Dumfries stole the headlines on Romelu Lukaku’s return to Serie A with a 94th-minute strike just as Inter looked to have dropped points at newly-promoted Lecce.
Lukaku nodded home from close range with just 81 seconds gone to give Inter the lead at the Stadio Via del Mare, an ominous sign for Lecce as he had netted against the southern side on his Italian top flight debut in 2019, a 4-0 thumping for Inter at the San Siro.
However Marco Baroni’s side, pushed on by passionate home support, refused to be cowed by their more illustrious opponents and drew level less than two minutes after half-time through Assan Ceesay, who slipped in a precision finish after being neatly put through by Federico Di Francesco.
Kristijan Bistrovic and Lameck Banda both stung Samir Handanovic’s fingers in the Inter goal but the away side had chances to win as they pressed in the latter stages.
Dumfries headed off the post and Lukaku was denied by flying goalkeeper Wladimiro Falcone just before the Netherlands wingback bundled in the winner which was harsh on the spirited hosts.
Silvio Berlusconi’s Monza were given a reality check in their first ever Serie A match, beaten at home 2-1 by Torino.
Aleksei Miranchuk opened the scoring two minutes from the break on his Torino debut, expertly finishing off Antonio Sanabria’s through ball following a quick passing move.
Sanabria doubled the away side’s lead with an acrobatic scissor kick midway through the second half, much to the disappointment of Berlusconi who was in the stands at the Stadio Brianteo.
Atalanta won Saturday’s other early match, 2-0 at Sampdoria through goals from Rafael Toloi and Ademola Lookman.