A second-half header from Mirko Vucinic gave AS Roma a 1-0 win at struggling AC Milan that lifted them into second spot in Serie A on Sunday.
Roma are three points behind leaders Inter Milan, who drew 0-0 at Palermo, failing to take full advantage of Juventus losing 3-1 at Napoli on Saturday.
Fiorentina missed the chance to move into second when they drew 0-0 in the late game at Genoa, who almost snatched a win thanks to the trickery of forward Leon.
Striker Vucinic, playing for the injured Francesco Totti, headed in Cicinho's cross at the near post to inflict more misery on mid-table Milan, who have yet to win at home in the league this season.
The European champions also had Massimo Ambrosini sent off when he picked up a second yellow for pulling Daniele De Rossi's shirt and conceding an 80th minute penalty.
De Rossi missed the spot kick when he tried to chip Dida and instead sent the ball over the bar but Roma held on despite two Alberto Gilardino headers going close.
Roma captain and talisman Totti had been ruled out with an ankle injury he picked up in their 2-1 win over Sporting Lisbon in the Champions League in midweek.
Vucinic replaced Totti against the Portuguese side, netting a superb winner, and the Montenegrin showed he could continue to fill his boots by bagging another in a nervous San Siro which has only seen Milan win twice in Europe this season.
"We will find the cure," under pressure Milan coach Carlo Ancelotti told Sky television. "The only certainty is that we will not change our system of play until the end of the season because it is the only one that complements these players."
Milan president Silvio Berlusconi added: "Unfortunately, in football there is a lot of irrationality. But there's no need to be worried, I'm not worried."
Inter lost keeper Julio Cesar and midfielder Dejan Stankovic to injury against Palermo and may be content with the point from a tricky trip to Sicily.
Stankovic was unlucky with a fierce volley before going off with a serious-looking injury while Cristian Chivu struck the bar for Inter in the second half with a curling free kick.
Zlatan Ibrahimovic also had a late shout for a penalty but Palermo were good value for the draw.
Stuttering Lazio are level on 10 points with Milan, 11 behind Inter after just nine games, having been beaten 1-0 at home by Udinese. Asamoah Gyan headed the winner on 78 minutes from Antonio di Natale's cross.
Only four goals were scored in Serie A during the first 45 minutes of Sunday's seven early matches but Parma and Livorno did their best to up the total in a seesaw battle at the bottom.
Parma eventually triumphed 3-2 to leave Livorno rooted to the bottom on two points.