Sassuolo will play Serie A football for the first time in their history after claiming the Serie B title with victory over Livorno on Saturday.
Sassuolo, the ambitious Emilia-Romagnan outfit, who will be joined in the top flight by runners-up Hellas Verona, needed one win from their remaining three fixtures to seal promotion but could only manage draws against Padova and Pro Vercelli before Saturday.
The odds looked stacked against Sassuolo when Domenico Berardi and Luca Antei were sent off, but Simone Missiroli's goal six minutes into stoppage time at the Stadio Alberto Braglia made history.
The club from an industrial town on the outskirts of Modena finally achieved promotion to Serie B in 2008 under the ownership of chemical magnate Giorgio Squinzi and, after finishing third last season, coach Eusebio Di Francesco has now guided the Neroverde into the promised land.
Hellas, meanwhile, ended their 11-year exile from Serie A by grinding out a goalless draw with Empoli at the Stadio Marc'Antonio Bentegodi.
Financial difficulties had seen the Gialloblu - the city rivals of Chievo - spend four years outside of the top two tiers of Italian football before returning to Serie B in 2011.
Livorno and Empoli, meanwhile, will contest promotion play-offs with Brescia and Novara respectively.
At the other end of the table, Vicenza, Ascoli, Pro Vercelli and Grosseto were relegated to the regional divisions of the Lega Pro.
Information from the Press Association was used in this report