The Czech broke Jovanovski twice in the first set before saving three break points in the second.
The unseeded Jovanovski hit 33 winners to only 13 for the 10th-seeded Dane. She will next face former French Open champion Svetlana Kuznetsova of Russia.
The 10th-seeded Wozniacki laboured for almost three hours in a struggle which ended in front of a standing-room only crowd as she lost to her 48th-ranked opponent in their first-round match.
The 19-year-old American is into the quarterfinals at a major for the first time.
At 19, Sloane Stephens is the only teen still standing after coming out on top of her third round clash with 18-year-old Briton Laura Robson, who is also rapidly improving and shocked eighth seed Petra Kvitova in the previous round.
After a week of setting age-related records and becoming the media darling of this year's Australian Open, the Japanese player bid farewell to the big stage for now after losing her third-round singles match on Saturday.
Date-Krumm, 42, had already become the oldest third-round contestant in 34 years, but she met her match in Serbia's Bojana Jovanovski who won a tense contest 6-2, 7-6 (7/3) in 1hr 46min.
Former World No.1 Caroline Wozniacki was pushed hard by Serbian qualifier Bojana Jovanovski in the first round of the Japan Open Monday, winning the match in a tense decider.
Maria Sharapova has backed to plans to silence tennis grunters even though the world number one is one of the worst offenders.
Recent top-10 player Andrea Petkovic of Germany has withdrawn from Wimbledon because of a persistent right ankle injury.
Sorana Cirstea of Romania routed second-seeded Bojana Jovanovski 6-3, 6-1 on Monday in the opening round of the Tashkent Open.
Serbian teen tennis player Bojana Jovanovski had two days to forget after she went to Carlsbad, New Mexico instead of Carlsbad, California for the WTA San Diego Open.
Top-ranked Caroline Wozniacki advanced to the third round of the Madrid Open by beating Bojana Jovanovski of Serbia 6-4, 6-4 Tuesday.
Former star Jelena Dokic reached her first semifinals in seven years by beating Bojana Jovanovski of Serbia 7-6 (4), 6-2 in the Malaysian Open on Friday.
Rising Serbian teen Bojana Jovanovski overcame Urszula Radwanska of Poland 1-6, 7-5, 6-4 to reach the Malaysian Open quarterfinals on Wednesday.