INDIANAPOLIS (AP) _ Diana Munz, a high school sophomore from the Cleveland suburb of Chagrin Falls, Ohio, upset Olympic gold medalist Brooke Bennett in the 800-meter freestyle finals Saturday at the U.S. Open Swimming Championships.

The 15-year-old Munz caught Bennett on the final 50 to win the race in 8 minutes, 36.23 seconds. Bennett, who had won the event in six consecutive major meets, finished in 8:36.88. The 17-year-old, a high schooler from Plant City, Fla., had the lead as the two began the final 100. But Munz completed it in 1:02.42, a full second quicker than Bennett's 1:03.87.

``We've been racing for a really long time,'' said Munz, who finished third in the event at the Pan Pacifics this year and second in the summer national championships with Bennett winning each race. ``She's a great swimmer, so it's been a big challenge.

``I hoped to beat her. I figured if I did, it would be great. I'm ecstatic. I'm so excited, shocked.

She was surprised by Bennett's approach.

``She's usually way ahead of me going into that final 100,'' Munz said. ``This time she was within my reach and I went all out all the way to the wall.''

Both teen-agers will meet again in next month's World Championships that begin Jan. 12 in Perth, Australia.

``I hope she'll be looking for me there,'' Munz said. ``I'm sure we'll both have to go faster to win there,'' Munz said.

Meanwhile, Slovakian Martina Moravcova and 1996 NCAA Swimmer of the Year Kristine Quance closed the meet by adding to earlier success in the three-day event at the Indiana University Natatorium.

Moravcova won her fourth individual event for Southern Methodist. The 21-year-old took the championship in the 100 freestyle in 55.93.

SMU teammate Rania Elwani, an Egyptian Olympian last year, was second in 56.54. Moravcova had won the 50 free, 200 individual medley and 200 free events earlier.

Quance, a former Southern Cal swimmer, recorded her third and fourth victories of the meet within about 35 minutes. Quance, who earned a gold medal in the Atlanta Olympics in the 400 medley relay, won the 200 breaststoke in 2:30.69.

That race began around 6:50 p.m., and by 7:25 she was back on the starting block on the way to winning the 200 butterfly in 2:12.69.

She had won the 100 breaststroke and successfully defended her championship in the 400 medley events earlier. Jenna Street, a 15-year-old from Jacksonville, Fla., was second in the 200 breast at 2:31.47.

Misty Hyman, who won the 100 butterfly on Friday, and went into the meet with the third-fastest 200 fly ever in U.S. history. She was caught by Quance on the final leg of their race and was second in 2:12.82.

Gustavo Borges, the 1992 Olympic silver medalist for Brazil in the 100 free at Barcelona and a triple winner for Michigan in the 1995 NCAA meet, won 100 free event in 50.51. Francisco Sanchez, a Venezuelan Olympian who swims for Arizona State, was a close second in 50.56.

Other winners Saturday in individual events were Stanford's Tom Wilkens in the 200 breaststroke at 2:17.03; Canadian Pietucha Przemyslaw won the men's 200 butterfly in 1:59.85 for Virginia; and Canadian Brent Sallee edged Spanish Olympian Frederik Hviid in the 1500 freestyle. Sallee finished in 16:14.01 and Hviid had a time of 16:26.99.