BEIJING, Aug. 20 (Xinhua) -- Two Balkan teams, Montenegro and Serbia, marched into the men's water polo semifinals after beating Croatia and Spain in the quarterfinals respectively at the Olympic Games on Wednesday.

    In a heated game, Montenegro upstaged 2007 world champion Croatia 7-6 and edged their way to set up a meeting with defending Olympic champion Hungary on Friday.

    "We are very disappointed because we expected to go to the medal games. The players, the coaches, it is everybody's disappointment," Croatia's coach Ratko Rudic said. "The beginning of the game was our biggest problem. We were not on the level we should have been."

    World league champions Serbia eased into the men's water polo semifinals with a comfortable 9-5 quarterfinal win over Spain. With the win, Serbia advances to the semifinals against the United States.

    "Serbia played better than us in every aspect. They dominated us and forced us to play poorly today. We didn't play badly, but Serbia played extremely well," Spain's driver Ricardo Perrone said.

    Spain will fight against Croatia for the fifth placing on Friday.

    Also on Wednesday, Italy beat Canada 13-11 and Greece beat host China 13-8 in the 7th-12th classification round.