Even though Mendy was Senegal's second leading scorer with 17 points, he sparked his team to an historic win, which ended Angola's nine-game winning streak at AfroBasket.
Carlos Morais hit five three-pointers on his way to 19 points but the Angolans wasted a superb opportunity to stay undefeated in the Group Phase.
Once again Gorgui Dieng proved crucial for Senegal as he finished with game-highs of 24 points and 9 rebounds.
Dieng and Mendy were the only Senegalese to score in double digits, while Morais, his younger brother Braulio Morais and Yanick Moreira were the three players with 10 or more points for angola.
As a result of the win, Senegal advance to the Round of 16 with a perfect 3-0 record, while Angola finished the Group Phase with a 2-1 record.
Turning Point: Senegal trailed most of the second half, but Mendy hit a three-pointer with 21 seconds left that got his team within 73-72. He then made a buzzer-beating and game-winning tap-in.
Stats Don't Lie: Senegal out-rebounded Angola 40-34.
Game Hero: For his tireless attitude Mendy was Senegal's player of the game.
The Bottom Line: The game could have gone either way. Senegal never gave up, suggesting how determined they are for the remainder of the competition. A technical foul called on coach Lopez in the last minute turned out to be costly for Angola.