Genoa and Napoli will face each other in a virtual promotion play-off next weekend after their waits to return to Serie A were prolonged this afternoon.
Genoa conceded in stoppage time to lose at Mantova while Napoli leapfrogged them into second with a narrow home win over Lecce in the penultimate matches in Serie B.
The Azzurri beat Lecce 1-0 with a seventh-minute header from Emanuele Calaio but also needed Piacenza and Rimini to avoid winning. Rimini drew 1-1 at Triestina while Piacenza beat Vicenza 2-1 with an 82nd-minute goal by Lucas Simon.
Genoa could have clinched promotion by winning - without any help from other results - but lost 1-0 to 10-man Mantova. Emiliano Tarana scored five minutes into second-half added time.
The two sides meet in Genoa in next Sunday's final round of matches with the winner joining champions Juventus in Serie A next season, although a draw will be enough for Napoli.
However, both clubs could still go up automatically under Serie B's complicated promotion rules. If the third-placed side finishes 10 points or more above the team in fourth then they go up automatically without the need for a play-off between third, fourth, fifth and sixth.
Napoli have 78 points, Genoa have 77 and fourth-placed Piacenza have 67. Piacenza host Triestina next Sunday needing a win for the play-offs to go-ahead.
Rimini, Mantova and Brescia are tied for fifth with 64 points and Bologna are next with 62. The quartet will be fighting for the final two play-off spots and hoping that Piacenza win and keep the play-offs on.
Napoli and Genoa are both trying to complete successive promotions after the two former Italian champions came up from the third tier of Italian football last season following equally controversial relegations.
Genoa won promotion to Serie A in 2005 but instead were demoted to Serie C1 when they were found guilty of match-fixing.
SSC Napoli were declared bankrupt in 2004 and a new club called Napoli Soccer was formed in the third tier. The club's name was restored to SSC Napoli last year after they won promotion to Serie B.
Juventus, who achieved promotion last month, lost 1-0 at Bari in Giancarlo Corradini's first game in temporary charge after Didier Deschamps' resignation last weekend. The Bianconeri had goalkeeper Gianluigi Buffon and captain Alessandro Del Piero away on international duty.
[Week 41 Review] - [Promotion/Relegation as it stands] - [Week 42 Permutations]