This makes me think of the Oregon/Boise State football game from last night. The Boise State player said something less than complimentary to the Oregon player so the Oregon player throws a sucker punch.
You have to learn to take the high road here and let that team revel in their obnoxiousness. You can walk off the field with your head held high knowing that not only did you play the best you could, you are clearly the better person.
The people who really matter (your friends and family, the umpires and the tournament organizers) will appreciate you much more than the 53-run scorers.
Youth baseball teaches so much about life and this is one of those experiences where I believe the "losing" team often comes out the "winner."