Roma beat AC Milan 1-0 on Saturday and ensured the Serie A leader ended the year with a loss.
Milan closes 2010 atop the league with 36 points, but the defeat means Juventus, Napoli and Lazio all have the chance to close within three points when they play on Sunday.
Roma had 29 points and was in the Europa League places.
Marco Borriello - on loan at Roma from Milan - struck in the 69th minute to bring the game to life for the last 20.
Milan was without five senior players and lost Andrea Pirlo early in the match to a thigh injury, but still created a number of chances either side of halftime.
"He (Borriello) is delighted," Roma coach Claudio Ranieri said. "He was excellent tonight. He held the ball up, kept the defense occupied and was an outlet for us."
Robinho came close to opening the scoring in the fifth. He raced into the Roma area, cut past Philippe Mexes, but shot wide of the far post.
Pirlo went off in the 22nd and from then on Milan missed his ability to control the tempo of the match.
Even so, Zlatan Ibrahimovic wasted a chance in the 35th. The Swede had only Doni to beat, but dithered and the goalkeeper blocked his effort.
"Doni saved us in the first half when he stopped Ibrahimovic," Ranieri said. "We kept our shape and didn't let Milan play. It wasn't easy though as Milan was very aggressive and showed it deserves to be in first place."
Borriello's goal was his ninth of the season. Menez crossed from the right and as Ignazio Abate attempted to clear, the ball rebounded off Borriello and into the net.
Ibrahimovic then had two more chances behind Roma's defense, but shot over with the first and was unable to control the ball with the second.
In the 77th, Milan goalkeeper Christian Abbiati kept the host in the game when he pushed Daniele De Rossi's long-range volley away for a corner.
With three minutes remaining Ronaldinho created a chance for himself, but acrobatically volleyed over the bar.
"I'm delighted with the team spirit, the way the team stuck to its task and took advantage when Milan slowed down after it had dominated the first half," Ranieri said.
Also, Luis Jiminez scored in the first half to give Cesena a 1-0 win at home to Cagliari.