Hucles, who scored twice in the Americans' 5-1 rout of France in Sunday's Algarve opener, tallied in the 60th minute from Abby Wambach's 35-yard ball into the box.
The Americans need only a tie -- and could get by with a loss -- on Thursday in Lagos against Sweden to advance to Saturday's championship game. The Swedes were beaten Tuesday by France, 3-0.
The Americans have shut out eight of 10 opponents in 2004, going 9-0-1 and winning China's Four Nations tournament and the CONCACAF Olympic qualifying tournament in Costa Rica. They are seeking their third Algarve Cup title in nine trips to the annual event held in southern Portugal. The United States won championships in 2000 and last year.
Hucles had scored just one goal in 29 previous international appearances before the Algarve Cup.