The US swim team opened their Duel in the Pool tournament against the Europeans Friday by setting a world record in the women\'s 400-metre medley relay. Missy Franklin, 16, gave the Americans the finishing kick they needed, swimming the freestyle anchor leg of the race for a total time of three minutes, 45.56 seconds. The US obliterated the old record of 3:47.97 which they set two years ago in the Duel in the Pool competition. Natalie Coughlin, Rebecca Soni and Dana Vollmer also swam the medley for the US on Friday.