AC Milan and Roma battled out a 0-0 draw on Sunday as both sides finished with 10 men while the game was delayed because of racist chanting.
The point kept Milan in third place and on course for a UEFA Champions League spot.
But red cards for Milan's Ghanaian Sulley Muntari and Roma skipper Francesco Totti, as well as more racist controversy, over-shadowed action on the pitch.
Muntari was sent-off for manhandling the referee as the official reached into his pocket to book Mario Balotelli.
Play was then held up for three minutes early in the second half as Roma fans were warned to stop making racist chants.
Roma went down to 10 men in injury time when Totti shoved an elbow into the face of French central defender Philippe Mexes.
Earlier, Edinson Cavani scored what may have been his final goal in front of Napoli's fans in a 2-1 win over relegated Siena.
Uruguayan international Cavani has been tipped to leave Napoli after a season in which his 28 league goals have secured a runner-up finish behind Juventus and guaranteed Walter Mazzarri's side Champions League football next season.
However Napoli's fans had to wait until the 73rd minute for the equaliser after Fabrizio Grillo had given Siena a 36th minute opener, Cavani nodding home from close range after Marek Hamsik's free kick had caused chaos in the Siena box.
Napoli looked to be heading for a draw but when Goran Pandev dummied Lorenzo Insigne's pass from the right Hamsik collected and coolly beat Siena 'keeper Gianluca Pegolo to secure the Neapolitans' 23rd win of the season.
Fiorentina's 20th win of the campaign, as they beat Palermo 1-0, closed the gap to seven-time European champions Milan to two points with just one round of matches left to play.
Udinese, Lazio push for Europa
Lazio and Udinese made sure the fight for UEFA Europa League places will go right down to next week's final round of games with 2-0 and 2-1 wins over Sampdoria and Atalanta respectively.
Sergio Floccari gave Lazio a 10th minute lead and Antonio Candreva made it two from the spot in the fourth minute of injury time, securing an 18th win of the season which kept the Biancocelesti in sixth, two points behind Udinese.
Udinese have enjoyed a strong end to the campaign and veteran striker Antonio Di Natale continued his purple patch by scoring both the northerners' goal to take his tally to 22 for the season.
Palermo and Siena followed in the footsteps of already-relegated Pescara.
It means Palermo return to Serie B for the first time since their triumphant 2003/04 season in Italy's second tier.
Coach Giuseppe Sannino, sacked from his post by Palermo president Maurizio Zamparini in September only to be re-hired in March after Gian Piero Gasperini suffered the same fate, said he was unsure of his future.
"It's not the right time to decide my future at the club, you can't make decisions with your heart. We have to sit down to discuss many issues," said Sannino.
"Everyone needs to accept their part of responsibility for this. I am not a miracle worker."
He added: "We need people who are not afraid to suffer and who love this shirt."
Genoa began the day with a four-point cushion over Palermo but are now five points ahead having played out a scoreless draw at home to Inter Milan.
Inter were the last Italian club to win the Champions League, in 2010, but having started this league campaign positively the Nerazzurri are set for a finish just above mid-table and will not play in Europe next season.
Andrea Stramaccioni's side have been decimated by injuries in recent months and this latest setback will heap further pressure on the 37-year-old coach.
Stramaccioni, however, claims to have the backing of Inter president Massimo Moratti as he looks ahead to an improved campaign in 2014.
"We have a strong relationship which is honest and sincere," said Stramaccioni.
"I'm optimistic and convinced that we can lay the foundations for a better campaign next season."