Ahmed Al-Sayed was taken off at half-time and replaced by Mohamed Samir as Al Ahli came back from behind to win in Cairo, thanks to a brace from Emad Meteb.
"Al-Sayed received a knock to his ankle and he was struggling during the first half," assistant coach Alaa Maihoub told the local press.
"I think the problem had an effect on us and Petrojet could have scored again after Al-Sayed's injury, but I also believe that Samir's performance was pleasing."
Maihoub praised the level of performance of both teams as he believes the contest with Petrojet to be a top clash in Egypt.
"It was a tough game and both sides played very well. I think we are the best two teams in Egypt in the meantime," added the former Ahli star.
Maihoub refused to point finger at goalkeeper Ahmed Adel for Petrojet's goal, stressing that the defence also were to blame.
"It was a joint error. The defence failed to apply the offside trap and then Adel was a little late to come out of his goal. I think everyone takes the blame," he said.
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