Fourth-round singles and third-round doubles matches continued through the eighth day on (21st Jan) of the Australian Open at Melbourne Park.
Tennis superstar Serena Williams has booked her spot in the quarter finals of the Australian Open.
After a first set that lasted just 20 minutes, Simona Halep fought back against Williams to win the second set.
Despite the world number one's best efforts, Williams prevailed 6-1, 4-6, 6-4.
Williams told Nine Network Halep set a difficult challenge for her.
"She's the number one player in the world and there's a reason why. She elevates her game and she plays well and she is just a great player. So in order for me to stay out there I had to, you know just play a little bit like I knew I could and I did, and I think that was obviously, hopefully that was the difference."
Williams will play Karolina Pliskova for a spot in the semis, after the seventh seed defeated Garbiñe Muguruza 6-3, 6-1.
Earlier in the day, Japan's Naomi Osaka made it through to her first Australian Open quarter final.
After losing the first set, the fourth seed made a strong comeback to defeat Anastasija Sevastova 4-6, 6-3, 6-4.
Osaka told the Nine Network she took inspiration from Stefanos Tsitsipas' performance against Roger Federer.
"I was watching him and also Tiafoe, and I thought they were playing really well, and just the fact that they came out here and played against some of the top players and won. I also want to do that. I think that's everyone's dream."
Also through to the quarter finals in the women's singles is sixth seed Elina Svitolina.
She took just over an hour and a half to claim a 6-2, 1-6, 6-1 victory over Madison Keys.
In the men's singles, world number one Novak Djokovic faced a tough challenge from Daniil Medvedev.
It took four sets for Djokovic to defeat the 15th seeded Russian 6-4, 6-7, 6-2, 6-3.
Speaking to the Nine Network, the Serb had nothing but praise for his opponent.
"Definitely it was a physical battle. You know, Daniil has been playing some really good tennis in the last six months. He has got a big serve, obviously a backhand. He doesn't make any unforced errors from that well. He defends well. He can come into the net, he can defend well from the back of the court. It was difficult to go through him."
Djokovic will battle it out with Japan's Kei Nishikori for a spot in the semi-finals.
The eighth seed defeated Pablo Carreno Busta 6-7, 4-6, 7-6, 6-4, 7-6.
Earlier in the day, Milos Raonic claimed victory over Alexander Zverev.
It took the Canadian just under two hours to beat his fourth seed opponent 6-1, 6-1, 7-6.
In the women's doubles, Australian Sam Stosur and China's Shuai Zhang came up against Alizé Cornet and Petra Martic.
They defeated their opponents 7-5, 6-3.
Australians Astra Sharma and John Patrick-Smith made it through to the third round of the mixed doubles.
It took them just over an hour to overcome Andreja Klepac and Edouard Roger-Vasselin 6-4, 7-5.
Fifth round singles matches begin today, with Australia's Ashleigh Barty fighting for a spot in the semi-finals.
