Spezia celebrated promotion to Serie A for the first time in the club's history despite a 1-0 home defeat to Frosinone in the second leg of their play-off final.
Thursday’s result at Stadio Alberto Picco made it 1-1 on aggregate, with the hosts joining the top flight courtesy of their superior position in the league table.
Frosinone midfielder Marcus Rohden claimed the only goal on the night in the 61st minute.
The visitors, who finished five places below their opponents in the regular season, pushed for a winner but Vincenzo Italiano’s men held on for a historic achievement.
Spezia were declared bankrupt in 2008 following relegation from Serie B and competed in Italy’s fourth tier the following season after being refounded.