"I went to sleep at 4:00am, I woke up at 6:00am, so solid two hours, I can't really sleep after my matches," said Osaka. "I just feel like my adrenaline's up more during the tougher matches so it makes it harder to sleep."
"It's definitely been a bit crazy time-wise," she added, having returned to the court to face Wozniacki less than 24 hours after defeating Andreescu. But if the two-time Grand Slam champion was exhausted, it did not show in a 6-4, 6-2 victory in 84 minutes against the Dane.
Osaka held off all seven break points she faced against Wozniacki. The world number four showed flashes of irritation as she let Wozniacki off the hook at 3-3 in the first set, tossing her racquet on the floor.