Mohamed Essam's late goal gifted 9-man Arab Contractors a precious 2-1 win against Zamalek to end their joyful mood following their Cairo derby win against Ahly on Friday.
The victory boosts Arab Contractors bid for a top four finish which would earn them an African spot next season.
Emad El-Nahas' men are now fourth of the table with 40 points two behind Pyramids FC and Zamalek who have each 42 points.
It is their first league victory over Zamalek since their 2-1 victory in April 2002.
Arab Contractors were off to a stunning start when Colombian winger Luis Hinestroza latched onto a long pass from Seifeddine Jaziri to score past the onrushing keeper in the 13th minute.
It could only become worse for Zamalek when captain and right-back Hazem Emam was forced to leave due to injury in the 17th minute making way for centre-back Mohamed Abdel-Ghani.
The Whites failed to respond against a well organized and compact Arab Contractors defence.
The pendulum seemed to swing Chelsea’s way when Arab Contractors defender Fadi Nagah saw the red in the 36th minute for bringing down Moroccan winger Achraf Bencharki before he could go clear on target after being clumsily dispossessed on the edge of the area.
However the hosts maintained their composure and managed to contain Zamalek's threats despite Bencharki creating opportunities for his front men which they could not capitalise on.
They had to wait until the 73rd minute when the Moroccan proved once again he is a class apart after volleying in the roof of the net a poorly cleared ball by Arab Contractors defence to grab the equalizer.
Zamalek attacked en masse seeking a late winner but they were left exposed at the back.
Pacy striker Mohamed Salem made a darting run to skip past two defenders but his shot was deflected into the path of Essam in front of an empty net.
Essam, who came off the bench in the second half, was booked for taking off his shirt during the goal celebration and received his marching orders three minutes later after bust-up with Zamalek defender Mahmoud "El Wensh" Hamdi.
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