Croatia vs. Serbia

The grudge: Having resented Serbian rule since the founding of Yugoslavia in 1929, Croatia was the first state to break away from Belgrade in 1991. The ensuing Serbo-Croatian war was a precursor to the war in Bosnia, which the Croats entered on the side of the Bosnian Muslims. The Dayton Peace Accords ended years of war and ethnic strife in 1995, but the rancor still lingers.

The competitors: The two countries met in the pool in the preliminary round of men’s water polo on Aug. 12.

The result: Croatia’s Samir Barac (celebrating above) scored three goals, and the Croats downed the Serbs 11-8.