Peng claimed a 6-2, 6-7 (4-7), 7-6 (7-4) decision in a marathon 2 hours, 32 minutes. Both players had a pair of third-set breaks before Peng edged ahead in the tiebreaker.
Kirsten Flipkens took another long three-set upset win, eliminating sixth-seeded Francesca Schiavone 2-6, 6-3, 7-6 (7-3). Schiavone didn't face a break point in the first set but was broken twice in the second set as Flipkens evened the match. Again, both players had two breaks in the final set.
Fourth-seeded Yaroslava Shvedova got past Lourdes Dominguez Lino 6-4, 6-1 and Chanelle Scheepers had six breaks in a 6-1, 6-2 win over Alize Cornet.
Mona Barthel rallied for a 2-6, 6-0, 6-1 win over Ashleigh Barty, winning 11 consecutive games over the second and third sets. Even though the match went three sets, it took just 70 minutes.