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Michael Phelps won his Olympic-record eighth gold medal with a little help from his friends. After Phelps gave the U.S. the lead in the butterfly leg of the 400-meter medley relay, anchor Jason Lezak held off Aussie Eamon Sullivan in the freestyle to nail down the win in a world-record 3 minutes, 29.34 seconds.

Photo: Heinz Kluetmeier/SI