AS Roma put Inter Milan's title celebrations on hold Wednesday when they beat the leaders 3-1 at the San Siro Stadium with goals by Simone Perrotta, Francesco Totti and Marco Cassetti.
Inter's first defeat of the season leaves them needing six points from the last five games to take their 15th championship.
Inter have 81 points, 13 more than Roma in second place.
A Roma side determined to spoil Inter's scudetto party controlled the first half and forced a series of good saves from Inter keeper Julio Cesar.
Serb midfielder Dejan Stankovic was the author of Inter's best effort of the first period, when his left-footed shot hit crossbar in the 38th minute.
But Roma deservedly took the lead before half time when Simone Perrotta tucked away a Cristian Chivu cross.
Inter looked more determined after the break and soon found the equalizer when Roma goalie Doni brought down Adriano in the area. Marco Materazzi scored the ensuing penalty.
Inter had a number of good chances to take the lead with Adriano, Julio Cruz, Zlatan Ibrahimovic and Maicon.
But Roma captain Francesco Totti silenced the home crowd when his deflected free-kick found the net in the 89th minute.
Cassetti sealed the win when he fired home a right-footed shot from the edge of the area five minutes into injury time.
Lazio drew 0-0 at home to relegation-threatened Chievo Verona, but remain in third place with 57 points.
The Roman outfit had the greater share of possession but created few chances against some tidy Chievo defending.
Both sides played the second half in 10 men, as Valon Behrami and Paolo Sammarco were sent off for a scuffle before break. Lazio's Luciano Zauri was also given his marching orders at the death for a second bookable offence.
AC Milan tightened their grip on fourth place and Italy's last Champions League slot with a 5-2 win over bottom club Ascoli. Milan have 53 points, four more than Palermo in fifth.
First-half braces by Alberto Gilardino and Brazil star Kaka and a 75th-minute goal by Clarence Seedorf gave Milan an easy win. The home side's goals were scored by former Italy midfielder Luigi Di Biagio and Stefano Guberti.
Here are the results of the other Serie A encounters played on Wednesday afternoon: Empoli 2 Atalanta 0, Livorno 2 Cagliari 1, Reggina 3 Messina 1, Udinese 1 Sampdoria 0.
On Wednesday night Parma play host to Fiorentina and Siena entertain Torino.
