When Mings and El Ghazi squared up to each other during Monday's 0-0 draw with West Ham, the 24-year-old skipper took responsibility.
Grealish told The Sun: “It happens sometimes in games. Emotions are running high. It probably wasn't what we wanted.
“We came in at half-time and we all spoke. Even JT had a little word and just said, 'Look, nothing's personal'.
“Then I said, 'You two can shout at each other now but before we go out there in the second half, you two are shaking hands and we're going out together'.
“The manager spoke about the first half, then everything calmed down. Before they went out for the second half, they shook hands.
“I think that's why the manager probably give me the captain's role, because I'm not afraid to say stuff.
“I'm not the oldest but because I've been at Villa my whole life and have the captain's armband now, a few of the lads do tend to listen."