Rome, Italy (My Sportsbook) - Serbian Milorad Cavic eclipsed Michael Phelps' world record in the semifinals of the 100-meter butterfly, setting up a Saturday night rematch between the two in the final at the World Swim Championships.

It was in Beijing last August when Phelps narrowly edged Cavic by 1/100th of a second for the gold medal, but on Friday the Serbian finished in a time of 50.01 seconds, bettering the mark of 50.22 set by Phelps at the U.S. Swimming Championships earlier in July.

Phelps, who was second in Friday's semifinal heat at 50.48 seconds, also won his third gold medal at Worlds, swimming the leadoff leg of the 4x-200-meter freestyle relay. The U.S. won in a world-record time of 6 minutes, 58.55 seconds, with Ricky Berens, David Walters and Ryan Lochte also participating in the final.

Russia came in second, .60 seconds off the pace, while Australia was third.

American Aaron Peirsol beat his own world record to capture the 200-meter backstroke in a time of 1 minute, 51.92 seconds, edging Japan's Ryosuke Irie by .59 seconds. Lochte was third.

Germany's Britta Steffen set the world record in winning the women's 100-meter freestyle in a time of 52.22 seconds. That bettered her old mark of 52.22 set at this meet from Sunday.

Serbian Nadja Higl won the women's 200-meter breaststroke in a time of 2:21.62 and Daniel Gyurta of Hungary (2:07.64) edged American Eric Shanteau by 1/100ths of a second to win the men's 200-meter breaststroke.

In other news, FINA, the governing body for world swimming, moved up its boycott of record-breaking bodysuits to January 1, 2010. The organization said the material used for swimsuits can be only "Textile Fabric(s)" defined for the purpose of these rules as material consisting of, natural and/or synthetic, individual and non consolidated yarns used to constitute a fabric by weaving, knitting, and/or braiding.

The list of approved swimsuits by FINA Executive on June 19, 2009 and published on the FINA website, is valid until December 31, 2009.