Mendy had a goal disallowed during the 2-0 win.
Zidane said, "I'm happy with him because he's only recently arrived. He can still improve a lot more and I'm happy to see that offensively he's contributing to the team.
"The other day he scored a great goal, today he could have scored again but it was disallowed when there was only a foot in it. He's a player who can get up and down for us and that's a good thing."
Zidane added: “I'm not going to comment on the fixture schedule. It was an important win and we've already got enough things going on. We've already spoken about these things and the fixture schedule is what it is.
"We didn't have a normal pre-season and we've got a lot of injuries. We'll just keep on going. I hope to welcome my players back because that's the most important thing and I'm not going to comment on anything else."