Former Manchester United defender Matteo Darmian scored the game’s only goal, firing home in the 76th minute after being found by Achraf Hakimi.
The win means Inter are 13 points clear of second-place AC Milan, who play on Monday, with five games remaining.
Defending champions Juventus are third after they were held 1-1 by Fiorentina.
Dusan Vlahovic converted a first-half penalty to give Fiorentina the lead but former Chelsea striker Alvaro Morata equalised when he fired into the top corner after spotting the goalkeeper off his line.