Inter trailed with 16 minutes remaining at Bologna, but Romelu Lukaku scored twice late on to send them back to the top of Serie A.
Romelu Lukaku was Inter's hero, converting an injury-time penalty for his second goal of the game as Antonio Conte's men came from behind to beat Bologna 2-1 at Stadio Renato Dall'Ara.
Despite enjoying the better of the first half, title-chasing Inter looked set to drop points when Roberto Soriano opened the scoring in the 59th minute, courtesy of a shot that took a deflection off Stefan de Vrij.