The Christian could respond in two ways. Firstly, on a god-of-the-gaps strawman and a genetic fallacy.
Evolution, given its truth, could only dismiss the existence of God if one used him to plug our knowledge on things we don’t know. But if Christianity holds to a completely transcendent God, an entity that runs the whole show, he cannot be explained away by human discoveries of how the universe works. Particularly because this God would have created the universe with all its mechanism. The Christian could respond by saying that evolution nor any other scientific discovery could explain the Christian conception of God away.
Secondly, an atheist philosopher by the name of Daniel Dennett has argued that belief in God is a by-product of the evolutionary process. If his conclusions follow then believe in God, he claims, can be discarded as irrational. However, one could catch Dennett in the trap of the genetic fallacy. One could argue that if God really did create humanity via an evolutionary process we would expect him to install a knowledge of him within us. That could be the case should the Christian God wishes for humanity to know him. Secondly, Dennett’s conclusion wouldn’t follow as to try and explain away someone’s belief away based on how they came to inherit that belief is a fallacy. It commits the genetic fallacy. For instance, a Muslim child is a Muslim only because he was born in Syria, but does that mean Islam is a false religion because he was born in Syria? That conclusion wouldn’t follow and the same would apply to evolution and belief in God.