Karolina Pliskova’s miracle Australian Open comeback against Serena Williams left her physically and mentally drained for Thursday’s semi-final loss to Naomi Osaka, the Czech seventh seed said Thursday.

Pliskova survived four match points and bounced back from 1-5 down in the third set to defeat Williams for a spot in the final four, with the 23-time Grand Slam champion admitting she was powerless as her opponent “just went crazy”.

The 26-year-old almost conjured another great escape less than 24 hours later after going down a set and a break in her final four clash with Japanese fourth seed Osaka.

She clawed back the second set and had Osaka worried after bringing up break point late in the third, but the US Open champion held on for a 6-2, 4-6, 6-4 victory.

The defeat snapped a 10-match winning run for Pliskova, including a title in Brisbane, and she said the hangover from the Williams’ epic took its toll.

“It was tough. If there was a day in between these two matches, it would have been be helpful for me,” she said. “Not only that, the [Williams] match was tough, emotionally tough too. I was missing maybe little bit of power today. I was doing everything possible, but just missing a little bit here and there.”

Pliskova said she had played a punishing schedule in recent weeks.

“I’ve had maybe 15 matches in the last three weeks. That’s a lot,” she said. “Maybe [a rest] day would help, but that’s how it is. We don’t have to talk about this.”

Pliskova has been a regular in the second week of Grand Slams in recent years, reaching the quarters or better seven times since late 2016, but is still searching for a breakthrough win.

Despite the loss, she was satisfied with her form and optimistic Slam success would happen.

“Of course, after every loss you are kind of disappointed, especially if it’s this close,” she said. “But on the other hand, it’s my best start of the season in my life, so I don’t want to be too negative. “The season is long, anything can happen. I’m feeling great with my game.”