Sassuolo clinched promotion to Serie A for the first time in its history on Saturday, finishing as Serie B champions following a last-gasp 1-0 victory over third-placed Livorno.
Hellas Verona joined Sassuolo as runners-up after a goalless draw against Empoli.
Simone Missiroli scored the decisive goal for Sassuolo with practically the last kick of the game after his team had been reduced to nine men, while Livorno also had a player sent off.
Sassuolo is a small town of around 40,000 inhabitants, near Modena in northern Italy, and its team was playing in the fourth division seven years ago. It was steered into Serie B in 2008, under current AC Milan coach Massimiliano Allegri.
It had lost in the playoff in two of the previous three seasons.
Livorno and Empoli will host Brescia and Novara respectively in the playoff semifinals.