Vanja Udovicic scored three times Saturday in leading Serbia past the United States 11-6 in the Olympic water polo tournament. Serbia advanced to 3-0-1 with one game left to play in Group B. The Americans lost for the first time in the tournament and dropped into second place. Ryan Bailey had two goals for the Americans. Montenegro is a half game behind the United States in the group standings. The top four from each of the two groups will reach the quarterfinals and the Americans are assured of doing that. Croatia stayed unbeaten in Group A with a 4-0 win over Croatia. Spain is second in the group with a 3-1 mark. The Americans finish group play on Monday against Hungary.