San Francisco Frontiers - Sabalenka rolls into last eight as Alcaraz steps up Melbourne bid

After brutal heat nearing 40C disrupted play on Saturday, temperatures eased to a comparatively cool 22C at Melbourne Park as the business end of the tournament started.

Belarusian top seed Sabalenka, a two-time Australian Open champion, opened the day on Rod Laver Arena and was forced to dig deep in the second set to see off 19-year-old Canadian Mboko.

Sabalenka won 6-1, 7-6 (7/1) and faces another teenager in American Iva Jovic or Kazakhstan's Yulia Putintseva in the last eight. That duo play later Sunday.

"What an incredible player for such a young age," said Sabalenka of 17th-seeded Mboko, who has emerged as a serious threat in the past year.

"I feel like I am a kid still! She pushed me really hard today and played incredible tennis.

"Happy to be through."

Sabalenka raced through the second-set tie break -- the 20th Grand Slam tiebreak in a row she has won -- to seal victory.

She has yet to drop a set at the tournament as her title charge gathers pace.

Mboko came through a gripping three-set battle with Danish 14th seed Clara Tauson to make the last 16 on her Australian Open debut.

But playing the world number one on centre court was a very different proposition and she looked nervous to begin with.

Sabalenka appeared poised to ease through in double-quick time, but Mboko showed signs of her rich promise to push the 27-year-old all the way in the second set.

Third seed Coco Gauff faces Czech 19th seed Karolina Muchova while Ukraine's Elina Svitolina takes on 18-year-old Russian Mirra Andreeva in the other women's round-four matches.

The winners will face each other in the quarter-finals.

- Alcaraz steps up -

Six-time Grand Slam champion Alcaraz follows Sabalenka on to centre court to take on American journeyman Tommy Paul after warning he was getting "better and better".

Alcaraz has never gone past the last eight in his four previous trips to Melbourne Park, with the Australian Open the only Grand Slam missing from his burgeoning collection.

The 22-year-old is bidding to become the youngest man to win the career Grand Slam of all four majors.

Should he get past Paul, either sixth-seeded home hope Alex de Minaur or Kazkahstan's 10th seed Alexander Bublik will be waiting for him.

They headline the night session on Rod Laver Arena.

Three-time finalist Daniil Medvedev survived a five-set fright in round three and could face another marathon against up-and-coming American Learner Tien.

Tien and former number one Medvedev met three times last year, with the younger man winning twice, including a five-setter in the second round of the Australian Open.

"Will try to do my best to maybe surprise him somewhere," said Medvedev, from Russia.

Whoever comes out on top will face third seed Alexander Zverev of Germany or the unheralded Francisco Cerundolo of Argentina.

B.Ramirez--SFF