The model, identified in Egyptian media by only one name, Mirihan, accused Warda of using threatening language when she rejected his advances.
"I know how to get your number. You don't know who you [are] dealing with. No one brushes me off," she quoted him as writing to her late one night last week.
Salah, 27, tweeted after Wednesday's match that women must be treated "with the utmost respect" but also that Warda should be given the chance to atone for his mistakes.
Women must be treated with the utmost respect. “No” means “no”. Those things are and must remain sacred. I also believe that many who make mistakes can change for the better and shouldn’t be sent straight to the guillotine, which is the easiest way out.
The issue was thought to have been resolved with a warning until a video clip surfaced online on Tuesday night purporting to show the player engaging in a sexual act with an unidentified woman. This led to the Egyptian FA to make a brief statement that Warda was expelled ahead of their second Group A game.
The off-field issue did not distract the tournament hosts, who ran out 2-0 winners against DR Congo. Salah got his tournament up and running with the second goal after Ahmed Elmohamady prodded home the first.