Hantuchova got by Schiavone, the No. 15 seed, 6-7 (8-10), 6-4, 7-6 (7-3) in a quarterfinal that totaled 263 points but only five breaks.
Hantuchova finished with the edge in points won -- 137-126 -- and breaks -- 3-2. She had two breaks in taking the second set and used another to get to the third-set tiebreaker.
Donna Vekic had the upset of the round with a 6-2, 6-1 romp past third-seeded Sorana Cirstea in 66 minutes. She lost the only break point Cirstea had but won nearly three-quarters of the points on serve, losing 11 points in eight games.
Also Friday, No. 16-seeded Magdalena Rybarikova raced past Madison Keys 6-3, 6-0 in 51 minutes.
The fourth semifinalist won't be determined until Saturday. Fifth-seeded Sabine Lisicki was tied with Alison Riske 6-7 (2-7), 6-2, 2-2 with Riske to serve when play was stopped Friday because of darkness.
Vekic is to play Rybarikova in the first semifinal Saturday. Vekic won their only previous meeting.
Hantuchova is 1-2 versus Lisicki and 1-0 against Riske.