The left-back, who earned a nomination for the August Premier League Player of the Month award with three assists for City, turned provider once again, having been introduced from the bench just after the hour mark in the League A Group 1 clash.
Les Bleus had opened the scoring through Kylian Mbappe inside the quarter-hour before Ryan Babel equalised on 67 minutes.
France restored their lead just eight minutes later though, as Mendy whipped in a trademark cross for Olivier Giroud to volley home the winner.
Meanwhile, Oleks Zinchenko, who bagged in injury time of Ukraine’s League B Group 1 victory over the Czech Republic on Thursday, came off the bench to feature in Sunday’s encounter with Slovakia, replacing Ruslan Malinovsky on 71 minutes in a 1-0 triumph.
Elsewhere, Ilkay Gundogan completed 84 minutes of Germany’s friendly victory over Peru. Leroy Sane was absent, having withdrawn from the squad following the birth of his daughter.
Die Mannschaft had to come from behind late on to secure the win, as goals from Julian Brandt and Nico Schulz cancelled out Luis Advincula's opener.