Olympic bronze medalist Dix also won his heat with a time of 10.03 seconds.
In the 400m race, Olympic champion LaShawn Merritt topped the men’s semi-finals in 44.78 seconds and former world champion Sanya-Richards Ross ran 50.81 seconds to win her women’s semi-final. Francena McCorory had the day’s fastest time of 50.55 seconds.
Two-time Olympic shot put silver medalist Adam Nelson, hampered by a groin injury, missed his chance to make the US team by finishing 15th.
The trials continue through next Monday.