Way too many decades ago, when I was on the high school water polo team, we were having a 6-on-5 practice. I normally played goalie, but for the practice I was needed in the field. My field skills were average since I did not play outside the goal that much.
I was assigned to play defense against one of our better offensive players. I could see the gleam in his eye as he took his position next to me. He was soon disappointed when I made a couple of good defensive plays.
On the next play, he did some nasty stuff under the water and won that round. This was not a surprise because in water polo there is plenty of nasty stuff that goes on under the water. On a good day the referees will catch about half of it.
On the following play I returned the favor and won that round. My efforts earned me a dirty look. We traded nastiness and victories for the next two rounds. At the end of it my teammate told me to stop. I just smiled. When he played dirty again, I returned the favor on the next play.