After dropping just three games in the first two rounds, Capriati, 27, breezed through the first set, looking as if she would cruise to victory again. But Loit's tricky lefthanded game began to click in the second set and she broke at the start of the third.
Capriati, who snapped a title drought of more than a year last week at New Haven, will face No. 11 Elena Dementieva of Russia in the next round. Dementieva beat American Amy Frazier, 7-6 (7-1), 7-6 (7-3).
On the men's side, sixth seed and 2001 champion Lleyton Hewitt of Australia took a 6-1, 3-0 lead over Radek Stepanek before the Czech retired with a lower back injury.