Just as in the men's event, Jamaica and the United States have dominated the global sprint scene in the last two decades and the United States took first blood on Sunday with an explosive performance by Gardner.
The 21-year-old winner of the US trials flew out of her blocks to open a two-metre lead in an instant and, unlike most of her more experienced rivals, kept the power on to drive through the line in 10.94 seconds despite a slight headwind.
"My coach said to get out at 60 and if felt good, finish," she said. "That wasn't necessarily all out. I think I have a lot left, that felt pretty comfortable so I'm a little scared!"
Team mates Alexandria Anderson and Octavious Freeman also looked sharp but defending champion Carmelita Jeter, who has missed much of the season through injury, appeared a touch off
the pace and finished second in her heat. Jamaican quartet Kerron Stewart, Shelly-Ann Fraser-Price, Sheri-Ann Brooks and Schilonie Calvert all progressed safely, Stewart the fastest in 11.02.
Blessing Okagbare, who set an African record 10.79 when winning last month's London Diamond League meeting, looks the only woman in the field capable of crashing the US-Jamaican party and the muscular Nigerian eased through her heat in 11.03.
Kelly-Anne Baptiste of Trinidad and Tobago, the third-fastest woman this year and bronze medallist two years ago, did not race after reportedly testing positive for drugs and leaving Moscow on Saturday.
The 2011 silver medallist and former winner Veronica Campbell-Brown and fellow Jamaican Sherone Simpson missed the championships after dope-test failures.
The semi-finals and final (1850 BST) are on Monday.