Inter hosted Udinese in the last 16 round match of the Italian Cup, which was played at Giuseppe Meazza and started at 23.00 GMT.
The blue-blacks took the lead 1-0 with Arnautovic in the 30th minute, and doubled the difference with Kristjan Asllani at 45+2.
There was no other goal in the match and Inter reached the quarter-finals of the Italian Cup.
National star Hakan Çalhanoğlu entered the game instead of Kristjan Asllani in the 63rd minute of the match.
Inter was matched against Lazio, who eliminated Napoli with a score of 3-1 in the quarter-finals.