Tyler Hamilton's gold led a three-medal haul for the United States in the cycling time trials, staking the American team's claim as king of the road races.
Hamilton's teammate, Bobby Julich, picked up the bronze, hours after Dede Barry won the silver in the women's race. No other nation in the Olympics has won more than two medals in the four road events.
"I believe we are one of the best cycling countries in the world, with Lance Armstrong winning the last six Tour de Frances and great results here today," Hamilton said. "It says a lot about U.S. cycling."
Hamilton edged defending men's time trial gold medalist Viatcheslav Ekimov of Russia by about 19 seconds, taking home the first American road gold since 1984, when Alexi Grewal won the road race in Los Angeles.
In the women's race, Leontien Zijlaard-van Moorsel of the Netherlands -- who suffered hip and shoulder injuries in a fall late in Sunday's road race -- successfully defended her gold medal by covering the 14.9-mile course in 31 minutes 11.53 seconds.
Barry was 24.09 seconds back. Switzerland's Karin Thuerig won the bronze, edging American Christine Thorburn by 19.93 seconds.
"I'm ecstatic," said Barry, an alternate in the 1996 and 2000 Olympics. "The last 10 minutes, waiting to see what would happen, were a little stressful. But I'm so happy. Everything worked out. It's such a great feeling."