ATLANTA (AP) _ The United States learned quickly just how tough the competition will be for the gold medal at the Olympic water polo tournament.

The Americans lost their opening game 10-7 to Italy, the defending gold medalist and reigning world champion.

Despite the loss, the Americans remain in contention. The preliminary round is played under a round-robin format, with four teams from each of the two six-nation groups advancing to the quarterfinals.

The U.S. team can redeem itself against Greece on Sunday.

The Italians took the lead with 4:19 left in the first quarter when Alberto Ghibellini slipped the ball under the arm of American goalkeeper Chris Duplanty.

Chris Humbert, the 6-foot-7 leading scorer for the U.S. team, tied it less than a minute later with a power-play goal from long range. But then the host nation went into a brief slump.

The Americans, who split two games with Italy before the Olympics, yielded three straight goals. They battled back, however as Mike Evans, a 36-year-old veteran playing his third Olympics, Chris Oeding and Wolf Wigo scored.

Amedeo Pomilio's second goal of the game made it 5-4 for Italy early in the third period and then Evans hit the post before Luca Giustolisi increased the lead for the defending champions.

The Americans turned the ball over on the next three plays, all with a man advantage in the pool, and never got untracked again.

In earlier games, a dramatic lob by Tamas Kasas with eight seconds left gave Hungary an 8-7 victory over Russia in a battle of medal contenders.

In the first match of the competition, Yugoslavia, a three-time champion when it still included six republics, returned to Olympic water polo by winning 11-8 over the Netherlands. Yugoslavia now consists only of Serbia and Montenegro.

Croatia, the second powerful team to emerge from the breakup of old Yugoslavia, also began with a victory, beating Greece 8-5 behind three goals by Dubravko Simenc.

Spain, silver medalist four years ago at home in Barcelona, cruised to a 9-3 victory over Germany, helped by good goalkeeping from Jesus Rollan and two goals apiece from Salvador Gomez and Miguel Oca.

Andrei Kovalenko scored his fourth goal of the game with 16 seconds left to cap a rally by Ukraine from a three-goal deficit in a 6-6 draw with Romania. Romania led 6-3 early in the last quarter, but Ukraine fought back as Kovalenko scored two of his goals in the late run.

With Hungary going for a fast break in the final seconds, Russian goalkeeper Nikolai Maximov swam far out to try to intercept the attack. But Maximov was called for a foul and while he tried to return to his goal, the ball was slipped to Kasas, who found the empty net with a long-range lob.

``The Russian goalkeeper went out of the goal and I knew I had to put it in,'' said Kasas, who celebrated his 20th birthday Saturday.