Shikha Uberoi proved no match for her Thai opponent Tamarine Tanasugarn and the US-based Indian eventually retired hurt, making an early exit from the Legg Mason Women's Pro Circuit in Washington.
Shikha was trailing 2-6, 0-2 in the second set when she threw in the towel.
Earlier, Shikha and her sister Neha had crashed out of the doubles event as well, with a 5-7, 2-6 defeat against Canadian Marie-Eve Pelletier and Sunitha Rao.
Neha, however, is yet to play her first round game that pits her against Alberta Brianti of Italy.
Meanwhile, Leander Paes teams up with Czech partner Martin Damm and the fourth seeds kick off their campaign in the 600,000 dollar Legg Mason Tennis Classic later on Wednesday.
In their first round match, they face wild card pair of Ramon Delgado of Paraguay and his American partner Rick Leach at court number two.
And if the Indo-Czech par crossed the first round hurdle, which should not be a difficult task, they would face either the Justin Gimelstob-Tim Henman pair or the Russian duo of Igor Kunitsyn and Dmitry Tursunov.