Sloane Stephens made an easy start to her Korea Open campaign on as Varvara Lepchenko also advanced to the second round.
Stephens, the third seed in Seoul, cruised past wildcard Han Na-lae 6-1 6-1 in just 53 minutes.
The American broke serve five times to claim victory at the hard-court tournament in her first appearance since her first-round exit at the US Open.
Last year’s runner-up Lepchenko was similarly untroubled in a 6-2 6-3 win over Spanish qualifier Paula Badosa Gibert.
The only seed to fall on Tuesday was Alexandra Dulgheru, the Romanian losing to qualifier Aliaksandra Sasnovich 6-3 6-2.
Veteran Kimiko Date-Krumm, champion in Seoul in 2009, brushed past Ajla Tomljanovic, avenging her defeat to the Croatian at the Tokyo International last week with a 6-1 6-2 win.
Top seed Irina-Camelia Begu beat qualifier Kateryna Kozlova 6-2 6-4, Johanna Larsson overcame Nicole Melichar 6-4 6-2 and Russian teenager Elizaveta Kulichkova battled to victory over Heather Watson 6-4 3-6 6-3.
Katerina Siniakova lost just nine third-set points in a 6-3 2-6 6-0 win over Irina Falconi and Christina McHale profited from a retirement.
McHale was leading Yaroslava Shvedova 6-4 1-2 when the Kazakhstani called it quits.