Top seed Sabine Lisicki kept her cool on a searing night Wednesday to power past Grace Min 6-1, 6-1 and into the quarter-finals of the Hong Kong Open.
Lisicki had spent almost two-and-a-half sapping hours on court the previous night in getting past Romania's Monica Niculescu in three sets, but was in a big hurry 24 hours later.
The German sealed the second-round victory over her American opponent in just 40 minutes as the mercury nudged 33 degrees celsius under the Victoria Park floodlights.
"Last night was a tough match," said Lisicki. "I eventually found my rhythm and I was able to take that into today."
The world number 31 will now have a day off before playing China's Zheng Sasai on Friday for a place in the last four after Zheng ousted the number six seed Yanina Wickmayer of Belgium in the biggest upset of the day.
Wickmayer is ranked 62, 40 places above her Chinese opponent, but she became the third of eight seeded players to fall in the inaugural $250,000 WTA event.
Former French Open champion Italy's Francesca Schiavone reached the quarter-finals when her veteran opponent, 44-year-old Kimiko Date-Krumm of Japan, was forced to retire at 4-0 down in the second set with a shoulder injury. Schiavone had taken the first 6-3.
Earlier, second seed Daniela Hantuchova completed the first-round action by brushing aside local wildcard Zhang Ling 6-1, 6-4.
World number 51 Hantuchova, who will now meet 20-year-old Belgian Alison Van Uytvanck in the second round on Thursday, was satisfied with her opening performance despite suffering in the blazing afternoon sunshine in the second set and having to leave court to change her sweat-soaked kit.
"It was definitely the hottest conditions I have played in and I suppose this was the reason why my concentration slipped a little bit at the start of the second set," Hantuchova said.
"It was impossible to stay on court. My dress was heavy and about a metre long (with sweat) and I had to change. The change helped me."