Being a gracious winner or a gracious loser includes keeping your graciousness when the other side is being snarky. In fact, that's probably when it's at its most important. Sooner or later, hopefully, they'll have to deal with the realization of what a jerk they were. Meanwhile, you won't have that problem if you don't succumb to being a jerk in response.
It's a tough lesson to learn, believe me I know. But it's a very important one.