The promising right-winger was tackled near the Hammers' penalty area, but Risha perceived his fall as an attempt to earn an undeserved spot-kick.
Emam was shocked when the referee showed him a yellow card, as he didn't protest against his decision, which was clearly wrong.
"I didn't raise objection against him, but he cautioned me anyway," he told FilGoal.com after the match.
The up-and-coming player also revealed that Risha accused him of inflaming the spectators.
"When I talked to him, he said (don't play games, I don't want the crowd to be angry at me)," Emam said.
The referee was heavily jeered by the Cairo side's fans shortly after making his controversial decision.
"I was the one who suffered a harsh challenge, and I didn't ask for a penalty-kick, so I don't see the reason why I received a yellow card," Emam added.
Emam will miss the upcoming league game against ENPPI for collecting his third booking.