Internazionale saw their lead at the top of the Serie A table cut to just one point after they were held to a 2-2 draw by Siena at the San Siro on Sunday.
The visitors twice came from behind to deny Roberto Mancini's side who would have lifted their third consecutive Scudetto had they claimed victory.
Roma's 2-1 win at home to Atalanta ensured the race for the title will go down to the final weekend.
In front of an expectant sell-out crowd Inter took an 11th-minute lead when Patrick Vieira powerfully headed in from close range before Massimo Maccarone equalised on the hour mark.
Mario Balotelli restored Inter's advantage just before the break, only for Siena to again draw level through Houssine Kharja's long-range strike after 70 minutes.
Inter had the chance to win the match 10 minutes from time when Marco Materazzi won a dubious penalty, but the Italy defender saw his spot-kick saved by Alex Manninger.
In Rome, Christian Panucci and Daniele De Rossi gave the Giallorossi a two-goal buffer which proved enough to claim a vital three points, even after Gianpaolo Bellini scored two minutes from time.
At the bottom, Livorno's relegation to Serie B was confirmed as they went down 1-0 at home to Torino.
Alessandro Rosina struck the only goal of the game four minutes before half-time to ensure the Turin club's top-flight survival.
Fiorentina moved back up to fourth spot to boost their hopes of qualifying for the Champions League with a 3-1 victory over 10-man Parma.
The result sees the Florence outfit move two points clear of AC Milan, who lost 3-1 at Napoli.
The Gialloblu took an early lead through Igor Budan but the hosts fought back strongly with goals from Mario Alberto Santana, Franco Semioli and Pablo Daniel Osvaldo.
The Ducale cause was not helped by the dismissal of defender Marco Rossi 10 minutes from time.
Milan's hopes of clinching the last Champions League spot were dealt a blow with Marek Hamsik, Maurizio Domizzi and Gyorgy Garics earning victory for Napoli.
Clarence Seedorf struck a stoppage-time consolation but it was not enough to prevent the visitors being dumped unceremoniously out of the top four.
Cagliari secured their survival as they defeated high-flying Udinese 2-0.
Robert Acquafresca fired the visitors into the lead three minutes into the second half before Andrea Cossu doubled their advantage eight minutes later.
Reggina also made sure they would be playing Serie A football next term with a 2-0 home win over Empoli.
Edgar Barreto and Nicola Amoruso provided the all-important goals in the second half to move their side up to 39 points in the table, five clear of the drop zone.
Empoli now have a tough task ahead of them as the defeat leaves them three points adrift of safety after Catania managed a 1-1 draw at Juventus.
A last-gasp Alessandro Del Piero strike earned Juve a point and denied visiting Catania the chance to secure their safety.
Jorge Martinez fired the relegation-threatened side ahead three minutes into the second half but Del Piero, whose side have already secured third spot, pounced in the dying seconds.
Catania will take a one-point advantage over Parma into the final day of the weekend.
Lazio salvaged a touch of pride from a disappointing season by winning 2-0 at Genoa, condemning their hosts to a third consecutive league defeat.
Goran Pandev put the Biancoceleste ahead in the 32nd minute before Tommaso Rocchi sealed the win in first-half stoppage time.
Sampdoria triumphed 2-0 at Palermo to continue their push for top-six finish, despite being guaranteed a UEFA Cup spot next season thanks to Roma's qualification for the Coppa Italia final in midweek.
Second-half goals from Antonio Cassano and Cristian Maggio saw off the challenge of Palermo.
