Once-mighty Napoli travel to mid-table Bologna amid more talk of refereeing favouritism in Italian football.
The unfashionable club from Italy's south were ripped apart 3-0 by Milan five weeks ago, but have quickly picked themselves up and after three straight victories are back in second spot three points behind the Rossoneri with just seven matches of the season to go.
Last week with all eyes on the north's top-of-the-table Milan derby, Napoli beat fifth-placed Lazio 4-3 in the match of the day to move two points above fading Inter and reignite hopes of a first scudetto since 1990, led by Diego Maradona.
"It has been an incredible season," said coach Walter Mazzarri, after seeing his side come back from two goals down against Lazio.
"We defeated the demons through strength of pride and character. Bologna will be the first of seven more battles."
However, after a stirring comeback in front of 75,000 at the San Paolo stadium, Napoli's euphoria was soured by suggestions the result was influenced by bad officiating.
Lazio president Claudio Lotito told Italy's Radiouno the match "unfair," pointing to a Christian Brocchi's shot that television replays showed had crossed the goalline and, at 3-2, a dubious penalty decision and the sending off of defender Giuseppe Biava.
His counterpart Aurelio De Laurentiis, who had reportedly clashed with Lotito at a league meeting in the days ahead of the match, leapt to his side's defence.
"For me it was a clean and fair game, completely above suspicion," the film producer told Napoli's Radio Marte.
"There's always the chance of a mistake in favour of one team or the other if the rules don't change [introduction of video technology].
"If Lotito called Cavani a diver, he's out of order. There's always been some theatrics in football but Cavani is not a cheat."
While the return of Argentine forward Ezequiel Lavezzi after a three-match ban has boosted Napoli, they will be without the suspended Cavani on Sunday.
Giuseppe Mascara is favourite to start against a mid-table Bologna side under criticism after a lacklustre display in the 3-1 defeat at lowly Brescia last week.
Coach Alberto Malesani has midfielder Gaby Mudingayi back in contention for a side that has relied heavily on the 19 goals of veteran striker Marco di Vaio.
Leaders Milan, with Zlatan Ibrahimovic back from suspension, face a tricky fixture away at fast-improving Fiorentina on Sunday.
Third-placed Inter, who followed their 3-0 derby loss with a 5-2 home humiliation by Schalke on Tuesday in the quarterfinal first-leg of the Champions League, will hope to arrest the slide when they host Chievo Verona on Saturday.
Two points above Lazio, fourth-placed Udinese face sixth-placed Roma at the Friuli stadium also on Saturday, while on Sunday fifth-placed Lazio play Parma in Rome and Juventus, two points behind Roma in seventh, host
