(CNN) -- Nine-man Inter Milan surged nine points clear of city rivals AC Milan at the top of Serie A with a dramatic 2-0 win in the San Siro on Sunday night.
Diego Milito gave the reigning champions the lead in the 10th minute, but they were forced to much of the game with 10 men after Wesley Sneijder was sent of in the first half.
Goran Pandev's 65th-minute goal sealed the win for Jose Mourinho's side, who then saw Brazilian star Lucio shown red in stoppage time before Ronaldinho saw his penalty saved at the end of a dramatic derby which could go a long way to deciding the outcome of the title race.
Sneijder hit the outside of the post before Inter took the lead as Goran Pandev's ball sent Milito clear to beat Dida in the Milan goal.
Dutchman Sneijder saw red on the half hour mark as his sarcastic gesture after Lucio had been pulled down saw him given his marching orders under strong protest.
Milan tried hard to level at the start of the second half as Julio Cesar saved a close range Clarence Seedorf header from a David Beckham corner before Ronaldinho was just wide with a volley.
Beckham, who earned a yellow card in the first half, sent in a series of dangerous crosses from the right, but it was Inter who sealed the win through Pandev's superb curling free kick.
In injury time Lucio was sent off for a second booking as he conceded a penalty but Ronaldinho's effort was saved by Cesar to complete a miserable night for his team.
Earlier on Sunday, Napoli won 2-0 at Livorno to move to within a point of third-placed AS Roma while Palermo beat Fiorentina 3-0 to go fifth.