Fadl was in the right place at the right time when right-back Ahmed Fathi sent a free kick from the left wing.
Esperance's shaky keeper Wassim Naouara failed to parry the precise free kick before the ball struck the arm of Fadl and rolled into the net.
The referee allowed the goal to stand, prompting Esperance's angry players to surround him in protest at his decision.
Fadl didn't deny handling the ball but assured that he didn't mean to trick the referee.
"The ball just hit my arm, I didn't mean to score that way," the former Ismaili hitman told FilGoal.com. "Refereeing mistakes happen all the time."
Apology
In the same match, the 30-year-old was guilty of spurning a golden opportunity in the 53rd minute that eventually led to his substitution few minutes later.
Doe outpaced his marker to control a long ball and skip past Naouara, whose untimely obstruction almost gifted Ahli a second goal.
The Liberian lost his balance though to miss out on a chance of directly slipping the ball into an empty net.
But he still managed to pull it back to Fadl, who fired over the bar with the goal at his mercy.
"I owe Ahli's fans an apology for wasting that chance. I don't know how it went too high," Fadl said.