Moussa Diaby scored twice to help Al Ittihad secure a 2-0 victory over Inter at the U-Power Stadium on Wednesday.
Diaby struck either side of half-time to ensure the triumph over the Serie A champions, and now has three goals in his first four games since his move from Aston Villa.
The defeat is Inter's first of pre-season, with Simone Inzaghi's side concluding their preparations for the new season against Chelsea this weekend.
Having been second-best in the opening exchanges, Al Ittihad took the lead in the 25th minute when Diaby was picked out by Houssem Aouar before firing the ball beyond
Yann Sommer.
Despite Inter registering seven shots to their opponents' four in the first half, they found themselves further behind two minutes into the second half.
A loose pass by Alessandro Bastoni was punished as Ahmed Al Ghamdi saw his effort saved by Sommer, only for the rebound to fall kindly for Diaby to score his second.
Milan improved in the forward areas but were unable to test Predrag Rajkovic as Laurent Blanc's side held on for the win in Italy.
Data Debrief: Diaby does the business
After scoring six times in the Premier League for Aston Villa in 38 appearances, Diaby has already scored half of that total in his first four games for Al Ittihad.
The Frenchman was in top form against Inter, registering the most shots (three) and shots on target (two), with his expected goals (xG) total of 0.24 only bettered by Benzema (0.55).