France's Amelie Mauresmo continued her destructive progress through the event with a 6-1 6-2 win over Spain's Anabel Medina Garrigues.
The fourth seed has only lost six games in three matches so far and was always in control against the world number 70.
Mauresmo did suffer a scare late in the second set when she needed lengthy treatment for a lower leg injury.
But she recovered to serve out the match, sealing her victory with an exquisite lob.
Mauresmo's career has been blighted by injury since she served notice of her talent in 1999 by reaching the Australian Open final.
She said the latest problem was a tightening of the muscles in her left leg which had been nagging her for several days.
"It bothers me a bit and I will really try to take care of it, but I don't really know where it comes from or what it is, so it's difficult to say," she said.
Asked if the problem could derail her title hopes here, Maursesmo said only, "I hope not."