Zamalek hopes of reaching the Champions League quarter finals became nearly impossible after losing 1-0 to Tunisian side Esperance at Cairo stadium on Tuesday.
A disappointing start for Frenchman Patrice Carteron on his return succeeding to Portuguese manager Jaime Pacheco who was dismissed last week.
Libyan winger Hamdi El-Houni scored the winner in the 73rd minute, firing his side to the competition's last eight after a deserved win.
The White Knights remain third with just two points after four games, six points behind leaders Esperance.
Algerian side MC Alger are second with eight points after defeating Teungueth of Senegal 1-0 on Tuesday.
Zamalek have a mountain to climb as they must win their two remaining games, including their away tie against MC Alger, and the latter lose their two games.
Despite being desperate for a win, Zamalek started the game with a slow rhythm, giving the chance to the visitors to control the game.
The hosts appeared toothless during the first half as they failed to make any real threat to the Esperance keeper Farouk Ben Moustafa.
Esperance could have gone up before the break when El-Houni skipped past right-back Ahmed Eid to go clear on target only to be denied by keeper Gennesh.
Carteron introduced midfielders Emam Ashour and Mahmoud 'Shikabala' Abdel-Razek after the interval to pile more pressure on the visitors but Zamalek failed to find the cracks in Esperance's compact defence.
Zamalek had their first real chance on goal in the 50th minute when Achraf Bencharki curled in a 25-yard free kick but it was deflected into the corner by Ben Moustafa.
The decisive moment was in the 73rd minute when El Houni received an excellent pass from Hamdi Nagguez on the edge of the area to send a well-placed shot into the bottom of the net.
Bencharki and Obama squandered a couple of chances later on to end the game empty handed.
The White Knights will face MC Alger on the 2nd of April before hosting Teungueth one week later.
(For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)