Serena Williams rolled back the years to reach the Australian Open semi finals, dismantling the second seed Simona Halep in straight sets.

The 23-time grand slam winner needed just 81 minutes to defeat the Romanian world number two 6-3 6-3.

Williams broke Halep's serve in the second game of the opening set, and despite giving that break straight back, she powered through the remainder of the first set to claim it 6-3.

And with her nose in front, she never looked back, comfortably advancing to her 40th Grand Slam semi final, remaining on course to win a record-equaling 24th slam title, and an 8th in Melbourne.

An inspiration on and off the court 🙌

Serena Williams is looking forward to her semi-final clash against Naomi Osaka #AusOpen pic.twitter.com/njPUJrzgMp

— Eurosport (@eurosport) February 16, 2021

Speaking afterwards on court, Williams says she's starting to peak at just the right time.

"Yeah, I definitely think this was the best match I played in this tournament for sure. Obviously I had to, going up against the number two in the world. I knew I had to do better and that's what I did, so I'm excited!

"I just realised I was making a lot of unforced errors in those games I lost and I knew I had an opportunity to play better. I just had to stay in there keep going and that's what I did," she said.

Williams will now face the third seed Naomi Osaka in the last four, after the 2019 champion easily saw off the challenge of veteran Hseih Su-Wei 6-2 6-2.

Osaka has gone onto lift the title on each of the three occasions she's advanced beyond the quarter finals.

Serena Williams says she's looking forward to taking on the "inspirational" 23-year-old.

"She's such a strong player on the court and an inspirational person off the court which is cool. And it's so good to see someone that is so inspiring on both things.

"I've been watching her and I'm sure she's been watching me and so I feel this is such a good opportunity for me, this is the first grand slam of the year and it was such an arduous offseason, so I'm just happy with every win that I get.