Earlier on Saturday Juventus had gone fourth after Fabio Grosso's winner gave them a 2-1 success at freefalling Fiorentina.
But the big game happened in Rome where both teams were hoping to close in on the champions and establish themselves as Inter's main rivals.Milan coach Leonardo said he felt his side had deserved to win but insisted they are in good shape to try and overturn their 3-2 Champions League deficit against Manchester United next week.
"I think the team possibly deserved a little more, particularly after the break. With all respect to Roma we're a little bitter that we didn't win," he said.
The single point moved Milan three points behind their city rivals with Roma three more further back, but Inter have a game in hand at home to Genoa Sunday.
A victory will send them six and nine points clear of their two rivals, which is why both will see this as a missed opportunity. Roma coach Claudio Ranieri as good as admitted he was not holding out any hope of catching Inter.
"It was a difficult game, we knew it would be. I'm very satisfied with how we played against Milan," he said. The tension of the occasion seemed to get to them in a game of little flowing football and few chances. Given that both sides had more to lose than gain, the first half was a predictably tight affair.
Roma started well and went close with a Daniele De Rossi shot narrowly wide and Julio Baptista forcing Cristian Abiatti into a smart save. But after the break Milan played with renewed determination and gradually started to dictate things without creating many clear cut chances.
Marco Borriello had one after a slip by centre-back Juan but chose to shoot from a tight angle rather than squaring to Klaas-Jan Huntelaar and Nicolas Burdisso blocked his effort.
Roma, though, still had chances on the break and 16 minutes from time Montenegro forward Mirko Vucinic headed John-Arne Riise's cross narrowly wide from 12 yards out.
Ronaldinho then came even closer for the visitors with a header from six yards from substitute David Beckham's pin-point right-wing centre.
In Florence, Fiorentina suffered the worst possible preparation for their Champions League second leg clash at home to Bayern Munich on Tuesday, a tie in which they trail 2-1 from the first game in Germany.
La Viola have now only won one of their last nine league games, losing six, and sit down in 10th place. They are also nine points behind fourth-placed Juventus.
Fiorentina boss Cesare Prandelli urged his team to put substance over style."Sometimes we need to think more about the result than playing pretty football, sometimes you need to know how to be more clinical otherwise you don't get results," Prandelli said.
For Juve it was the perfect way to bounce back following last week's 2-0 home defeat to Palermo.
Juve were off to a flying start, ahead through Diego after just two minutes in contentious circumstances.Antonio Candreva played a clever ball in behind the Fiorentina defence with Diego looking offside.
But he sold goalkeeper Sebastien Frey two clever feints, leaving the Frenchman sprawled on the floor, allowing the Brazilian to round him and roll the ball into an empty net.
Fiorentina equalised on 32 minutes, but it was due to woeful Juve defending. Massimo Gobbi sent a 40-yard cross-field ball from left to right.
Juve full-back Paolo De Ceglie dithered and Manninger left it too late to come for the ball allowing Marco Marchionni, the smallest player on the pitch, to nip between the pair and head home from eight yards against his former club.
The winner came on 68 minutes substitute Grosso overlapped down the left, took a pass from Mali midfielder Mohamed Sissoko in the box and curled a shot from an angle high and beyond Frey's reach.