Following Wednesday's downpours, Kerber was first on Grandstand 1 and required just an hour and 20 minutes to see off Melanie Oudin, 75 60. In extremely humid conditions, at first the top seed struggled, dropping the opening two games, before rallying to pinch the set.
"It's tough here because the humidity is very high - I was sweating so much after only two games," Kerber said. "In the end I was just happy to win this match."
Kerber admitted in her post-match press conference that the previous day's wait had played on her mind. However, it didn't show in the second set, as she broke in the opening game and then rattled through the remaining five for the loss of just six points.
"Yesterday was a long day for us because we were waiting until 10 o'clock," she added. "It's not easy to wait a whole day and then come back the next day and play a good match. I'm happy that I won it and finished before the next rain came!
"I think the first set was very close and very tough, and she was playing very well. I just tried to find my rhythm and came into it in the second set and from that point I was playing very well."
Meeting the German for a place in the semifinals will be defending champion Magdalena Rybarikova. Last year, Rybarikova did not drop a set all week, but following a hard-fought 75 57 75 win over fellow Slovakian Jana Cepelova she has now dropped two in as many matches this time around.
"For sure, there is a lot of pressure this year," Rybarikova said. "She's a real fighter and she was fighting so hard for every point so I'm really happy to get through."
Against Kerber, who she will be facing for the first time, Rybarikova is looking forward to her new role as underdog. "She's a great player, a Top 10 player, and I have to play relaxed.
"We've never played, so it's going to be something new, and I'm for sure not going to be the favorite and I will just try to do my best."
Joining them in the quarterfinals will be No.3 seed Ekaterina Makarova, who followed up her opening round win against Eugenie Bouchard with an even more impressive 62 60 dismissal of another talented teenager, Caroline Garcia.
Next up for Makarova is Monica Niculescu, after she fended off two match points to oust No.8 seed Madison Keys, 61 26 76(6). Also advancing on Thursday were, Alizé Cornet, Sorana Cirstea and Paula Ormaechea.