Aryna Sabalenka fought off one teenage challenger but finds another in her path to the Australian Open semi-finals.
World No 1 Sabalenka looked to be cruising to victory against 19-year-old Victoria Mboko at 6-1 4-1 only for the Canadian to show just why she is so highly rated.
Mboko saved three match points at 5-4 but Sabalenka regrouped and won a 20th consecutive grand slam tie-break in dominant fashion to claim a 6-1 7-6 (7-1) victory.
Sabalenka was hugely impressed by Mboko, who is now on the verge of the top 10, saying: "She's an amazing player. It was quite a fight.
"I'm super happy that I was able to close this match in straight sets. The second set was a bit tricky. But I'm happy with the level I played. Happy to be through."
Next up for Sabalenka is an even younger opponent in American Iva Jovic, who only turned 18 last month.
The teenager followed up her maiden top-10 win against Jasmine Paolini by swatting aside Yulia Putintseva 6-0 6-1 in just 53 minutes.
Jovic picked Sabalenka at the end of last season as the player she most wanted to face, and she will now get her wish, with the teenager saying: "I think I'm just going to try to keep taking care of my side of the net.
"Obviously she's number one for a reason and had so much success at this tournament, but that's what I want.
"I said it last year, I hope to be able to play her this year because you definitely want to play the best and see how it goes. So I'm just really excited."
Sabalenka is maintaining her formidable record in Grand Slams, with the top seed, who is bidding for her third title here in four years, having made at least the quarter-finals at every major tournament she has played since the French Open in 2022.
Jovic already has 11 victories this season, more than any other woman, and is the youngest player to reach the quarter-finals at Melbourne Park without dropping a set since Venus Williams back in 1998.
She has been tipped as a future world No 1 by her idol Novak Djokovic, with whom she shares Serbian heritage and who has given her advice on her game this fortnight.
"Actually I spoke to Novak yesterday a little bit. So it was pretty incredible," Jovic said in her news conference ahead of her third-round match with Paolini. "He gave me some very attentive tips for my game and something I can try to incorporate into this match that I just played."
The connection was helped by the fact that her father is Serbian, and Djokovic, is a national icon in his native Serbia.
Jovic has regularly visited Belgrade and the southern town of Leskovac, where she has extended family.
Heritage also explains why Monica Seles and Djokovic were huge inspirations for Jovic when she grew up in the US and pursued a tennis career.
American Coco Gauff reached the quarter-finals after a battle with Czech Karolina Muchova, the third seed emerging with a 6-1 3-6 6-3 victory.
The result bodes well for the American, who has won every tournament in which she has beaten Muchova, including the 2023 US Open.
"I think today I didn't panic. I felt like the second set could have easily went my way," Gauff said. "So I knew I just had to capitalise on those chances in the third set and I did that."
What started as a demolition job quickly turned into a compelling see-saw battle at Melbourne Park, with Gauff storming to a blistering 5-0 lead in just 20 minutes.
Muchova, who arrived with two top-10 wins under her belt in Brisbane, did not get on the board until the sixth game and by then the opening set had already slipped away as Gauff closed it with clinical efficiency.
The tide turned in the second set, however, with Muchova breaking twice to establish a 4-1 lead as Gauff struggled with her serve and made double faults.
When the chance to serve for the set arrived, Muchova did not waste it, serving to love to claim a set over Gauff for the first time in five meetings.
Gauff, who constantly looked to the players' box in the second set, came out swinging in the decider, forcing more errors from Muchova to go up 4-1.
A thrilling seventh game had both players scrambling in long rallies as the momentum shifted back and forth until Gauff fired a backhand winner and screamed in triumph.
Muchova saved three match points before Gauff sealed progress to the last eight.
"She plays with so much variety," Gauff said. "You never know what you're going to do.
"In that last game I was trusting my second serve, which I feel like is a stepping stone in the right direction to be able to hit as many second serves in the court that I did, especially in the two games that were long holds."
A good omen for Gauff, though, is that every time she has beaten Muchova, she has gone on to win the title.
"I didn't know that, but I don't think it's a real thing," said the American. "I think I just usually play her later in the tournaments, so it just happens to be like that. I don't think I'm going to think about that but, if I do win, then I guess I have her to thank."
Ukrainian 12th seed Elina Svitolina knocked out Russian eighth seed Mirra Andreeva 6-2 6-4 to set up a quarter-final clash with Gauff.
Svitolina is through to her 14th career Grand Slam quarter-final and six of them have come after her return from maternity leave.
Watch the ATP and WTA Tours, live on Your Site or and the , giving Your Site customers access to over 50 per cent more live sport this year at no extra cost.
