Standout swimmers Claire Curzan of the United States and Pan Zhanle of China won their fourth gold medals at the world championships on Saturday. Curzan completed her set of backstroke gold medals after earlier winning the 50 and 100, plus the 4x100 mixed medley relay. Pan and China won the 4x100 mixed freestyle relay, which isn’t on the Olympic program, ahead of Australia and the U.S. There was another strong lead-off swim from Pan, who earlier in the championships swam the fastest 100 meters in history during the 4x100 men’s freestyle relay.