Inter Milan beat Juventus 1-0 at the Delle Alpi stadium on Wednesday, allowing defending champions AC Milan to return to joint top of Serie A with a 1-0 win at home to Chievo.
Juventus and Milan both have 70 points with Inter in third on 59 with six games remaining, including a potentially decisive clash between the leaders on May 8.
Argentine Julio Ricardo Cruz headed home the winner for Inter in the 24th minute of a game in which Juve twice struck the woodwork.
Milan, whose defeat at Siena on Sunday allowed Juve to go into Wednesday's games with a three-point lead, beat Chievo with a 65th-minute strike from Dutch midfielder Clarence Seedorf.
Roma's miserable season continued as Francesco Totti was sent off in the second half of their 2-0 defeat at home to lowly Siena.
Inter remain unbeaten away from home this season after victory in what is dubbed the 'Derby d'Italia'.
Juve went close to an early lead when their Brazilian midfielder Emerson headed against the bar in the 18th minute.
Six minutes later Inter got the decisive goal when Brazilian Ze Maria swung in a cross from the right flank and Cruz rose well at the back post to beat Gianluigi Buffon with a perfectly placed header.
After the break Juve's Swedish striker Zlatan Ibrahimovic went close twice, shaving the post with a 20-metre drive and then having a fiercely struck free kick saved by a full-stretch Francesco Toldo.
"We couldn't have done more than we did. We created chances but Toldo made three good saves," said Juve coach Fabio Capello.
"Milan are a very strong team but I am still convinced we can go all the way," he added.
HARD GOING
Milan found it hard going against a well-organised Chievo defence but had a Hernan Crespo effort ruled out for offside in the 24th minute.
The breakthrough came when Seedorf played a neat exchange with Kaka, burst past two Chievo defenders and rattled home a shot from just inside the area.
"That is a vital result for us which keeps the title in the balance," said Milan coach Carlo Ancelotti.
"To win the title we are going to have to show great mental and physical strength. It will be a very intense duel -- there are six games to go and all of them present hidden dangers."
Massimo Maccarone and Enrico Chiesa were on target for Siena in their win at Roma while all three teams in the fight for the fourth Champions League qualifying slot drew.
Udinese were held 1-1 at home by Livorno while Sampdoria were drew by the same score at struggling Parma.
Palermo striker Luca Toni scored twice in his team's 3-3 draw against Brescia which saw red cards for Brescia's Simone Dallamano and Palermo's Christian Terlizzi.
Sampdoria are fourth on 52 points with Udinese on 50 and Palermo on 48.
Fiorentina remain in relegation trouble after an injury-time goal from Messina's Arturo Di Napoli cancelled out Dario Dainelli's opener.
