Smashing her sixth record in five weeks, South African Penny Heyns lowered her own mark today in the 200-meter breaststroke semifinals at the Pan Pacific championships.

It was the eighth record to be set in five days at the event, and the second of the meet for Heyns. She also lowered the 100 record in the preliminary heats.

American Mary T. Meagher's 18-year-old record in the 200 butterfly survived the record rush as Australian Susie O'Neill missed her chance.

O'Neill, 26, was under record pace at 150 meters but could not finish it off. She finished with a time of 2 minutes 6.60 seconds, the same as her best before her 2:06.53 on Wednesday. She was unable to lower Meagher's 2:05.96 set Aug. 13, 1981, in Brown Deer, Wis.

During her five-week run, Heyns has lowered the 100 and 200 three times each.

"To be honest, I was really uptight about it all last night," Heyns said. "I have to say this morning I felt it was time to go home. I was really tired of racing, but I thought that's not why I swim."

Heyns broke four world records last month in Los Angeles, two in each event, and her 2:24.42 Wednesday was nine-tenths of a second under her 2:24.51 on July 18.

O'Neill faced pressure before the race and even Meagher, now Mary Plant, said she hoped O'Neill would break swimming's longest standing record -- men's or women's.

"One day, hopefully, maybe, I can do it," O'Neill said. "I want to keep swimming until I do. Maybe I'll be around at 35 at this rate."

Jenny Thompson, who broke Meagher's 100 butterfly world record Monday -- the second-oldest mark -- returned to action with the fastest qualifying time from the semis of the 100 freestyle.

She also won her 21st Pan Pacific gold medal as the U.S. 800 freestyle relay team swam the second fastest time. Thompson, Lindsay Benko, Ellen Stonebraker and Cristina Teuscher finished at 7:57.61, beating the 1994 Chinese team's time of 7:57.96 but missing East Germany's world record of 7:55.47 from 1987.