Karolina Pliskova revelled in the "best comeback ever" after her incredible win over Serena Williams in the Australian Open quarter-finals. 

The Czech seventh seed came from 5-1 down in the final set and saved four match points to claim a 6-4 4-6 7-5 victory in Melbourne on Wednesday. 

Pliskova, who will face Naomi Osaka in the last four, said there was no doubt it was her best fightback. 

"Well, normally I'm having lot of comebacks, but maybe like from being a set down or a break down, so nothing like this," she told a news conference. 

"I think it's going to be the best comeback ever so far in my life."

Williams rolled her ankle when serving for the match in the seventh game of the final set, but the 23-time grand slam champion praised her opponent. 

Pliskova, into her third major semifinal, said she tried to pay no attention to Williams' side of the court. 

"Whatever is happening on the other side, I just try to block it. Either it's positive or negative, whatever is there, it's just not my business. I'm sorry, but that's how it is. I know once I start to think about that, it's bad," she said. 

"That's what I did at that time. But I was like, 'Yeah, maybe something little bit happened, but she's still on serve, even if she loses this game, it's still 5-2.' I didn't really think about it, that maybe there's going to be a chance at that game." 

"But she did I think double-fault. I really went for my shots. I didn't feel like she played something really bad that game. Maybe the double-fault was a big help. Otherwise, I don't think she did anything actually that bad." 

"I thought she a little bit was missing more than she was the set and a half [prior]. But I was more aggressive. That's what was working in the first set, so that's just what I did."