Melbourne - Simona Halep said she was close to playing "100 percent" despite her aching body giving her sleepless nights as she reached the Australian Open last eight on Monday.
Halep has spent a shade under eight hours on court in four matches so far, including an epic 3hr 44min against Lauren Davis on Saturday which the Romanian won 15-13 in the final set.
"First day after the (Davis) match was pretty OK," the top seed told reporters after a 6-3, 6-2 victory over unseeded Naomi Osaka of Japan in 81 minutes.
"Last night was really tough. I couldn't sleep. I had pain everywhere.
"But I slept before the match two hours, and worked perfect, perfect hours. I was, like, fresh after that. I felt good."
Halep, who last made it this far in 2015, said she had more confidence in her troublesome ankle that she rolled in her first-round match.
"Ankle is still sore. But, you know, I'm not thinking about that any more," she said. "I saw that I can win matches with it.
"Maybe I get used to the pain and I'm not thinking that much that something can happen. Just taking every point.
"I'm trying to play 100 percent, which I was close today, to run normal and to run a lot. But I still feel it. It's there, but I can handle it."
The big-hitting Osaka had her chances, notably in the fifth game of the first set when she squandered five break points on the Halep serve.
The Romanian compounded Osaka's disappointment immediately with a break of her own and said it was a turning point.
"Yeah, after I took that game and those points, I felt more confident. I felt that now I can push the pedal and just go through the match," she said.
Halep served out to take the set in 42 minutes and immediately broke the Japanese player again to start the second.
The players matched each other with 22 winners apiece but Osaka's 31 unforced errors ultimately proved her downfall against the consistent Halep.
The top seed is guaranteed to meet a Czech opponent for a place in the semi-finals, either sixth seed Karolina Pliskova or Barbora Strycova, the 20th seed.
"Well, both of them are very tough. Even if I played with big hitters this tournament, Pliskova is always dangerous. She's playing great these days," said Halep.
"With Strycova, I played a few times. Was tough because I have to run a lot.
"So I'm looking forward to playing the quarter-finals again," said Halep who reached the same stage in 2014 and 2015.
"Third time lucky, maybe."