By Sarah Young

LONDON (Reuters) - American Maggie Steffens made the most of her Olympic debut on Monday as the 19-year-old Californian scored seven goals in a 14-13 win over Hungary on the opening day of the women's water polo tournament.

Steffens's talent and poise in front of goal stood out on a day that otherwise contained few surprises, with the favored U.S. and Australian squads, the 2008 Beijing Games silver and bronze medalists respectively, securing wins.

Steffens, who watched from the stands when her sister and team mate Jessica competed in Beijing four years ago, said she felt "awesome" after recording the biggest Olympic debut goal tally in the history of women's water polo at the Games.

"Was I surprised? No. She has so much potential in her and I think she's been waiting to bust out of her skin," Jessica, 25, said of her sister's performance.

The U.S. team has the Olympic gold medal firmly in its sights, according to Maggie, who deferred her place at Stanford University in California to concentrate on water polo.

"This is more important. Stanford can wait for the possibility of a medal," Maggie, sporting red scratches on her chest after scrapping against the Hungarians in this most demanding and aggressive of sports, told reporters.

U.S. captain Brenda Villa, 32, who is competing in her fourth Olympics, praised the younger Steffens, saying that it was not just the goals she scored but the chances she created which made her a stand-out player.

"She's a youngster but you would never tell in the water, she plays like she's being playing at this level for a long time," Villa said.

The U.S. looked the stronger side, but came up against a tough Hungarian team which responded to every U.S. move in a thrilling match that went down to the wire after a Hungarian goal in the final minute.

In the earlier games, Australia overcame a series of Italian retorts for a 10-8 victory, while Spain, playing in its women's Olympic water polo debut, used a series of outside shots to pound China 11-6.

Britain's women's water polo team almost rustled some feathers in what was their first ever Olympic appearance, going down 7-6 to Russia, a country with a strong water polo tradition and the only European nation to contest each women's water polo Olympic tournament since the sport was introduced in 2000.

The women's competition in London is considered much more open than at previous Games with defending Olympic champion Netherlands and reigning world champion Greece both absent after shock defeats in the qualification stages.

Australian coach Greg McFadden played down his team's status as one the favorites.

"I believe there's six or seven really good teams there. This is the most open Olympic games since I became involved in 2004," he told reporters.

Fielding a young team whose qualification was a result of its host nation status, Britain put on a smooth display of water polo but fell short of matching up to an organized Russian side.

"It was really great for everyone to realize that we do deserve to be here. Obviously (I'm) disappointed but we've got to take the positives from it, they didn't have anything more than us," Britain's captain Fran Leighton said.

There are eight teams in the women's tournament, split into two groups. All teams will qualify for the knock-out stages but securing a top position in the group will theoretically present an easier route to the later stages of the contest.

(Reporting by Sarah Young; Editing by Frank Pingue)