Recently built a PC for my son and now it seems he's all about crushing his dad on 1 vs 1 games. 
We have CS:Go and Max Payne 3 so far, but can anyone recommend any others that can definitely play 1 vs 1 private matches where the maps aren't too huge?

We have CS:Go and Max Payne 3 so far, but can anyone recommend any others that can definitely play 1 vs 1 private matches where the maps aren't too huge?