Mario Balotelli scored twice, including a hugely-controversial penalty three minutes into stoppage time, on his AC Milan debut to give them a 2-1 win over Udinese on Sunday, three days after completing his move from English champions Manchester City.
Furious Udinese players surrounded the referee to protest and police came onto the field to protect the official after the final whistle.
Balotelli was included in the starting line-up at the last minute after Giampaolo Pazzini pulled out during the warm-up.
The maverick Italy striker, who moved to Milan for a fee media reports put at 20 million pounds, opened his account by turning the ball in from six metres in the Serie A game against Udinese after Stephan El Shaaraway's cross from the left was deflected to his feet.
He nearly added another two minutes later with a dipping shot which was turned over by the bar by Udinese goalkeeper Daniele Padelli.
Giampiero Pinzi equalised on the break in the 55th minute when Udinese caught Milan napping and the home defence suddenly began to look vulnerable.
Balotelli was close in the 85th minute with a low free kick which Padelli turned around his post.
The match ended in uproar when Thomas Heurtaux tackled El Shaaraway who fell theatrically in the area and the referee pointed to the spot. Balotelli calmly converted to lift Milan to fourth in the table, ahead of rivals Inter Milan on goal difference.
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