PHOTOS: Serena consoles Ukrainian teen after win

'I kind of liked that. It shows she wasn't just there to play a good match, she was there to win. She wanted to win. That really broke my heart.'

Serena Williams powered into the fourth round of the Australian Open on Saturday with a 6-2, 6-1 demolition of Dayana Yastremska then consoled the Ukrainian teenager after leaving her in tears.

The 37-year-old Williams, chasing a record-extending eighth Melbourne title in the professional era, barely broke sweat on a sunny afternoon at Rod Laver Arena as she racked up 20 winners and beat the 57th-ranked 18-year-old in a breezy 67 minutes.

"As she was walking towards the net, I could tell she was quite upset," Williams told reporters. "I kind of liked that. It shows she wasn't just there to play a good match, she was there to win. She wanted to win. That really broke my heart.

"I think she's a good talent. It's good to see that attitude."

Yastremska rolled her right ankle midway through the match and took a medical time-out to have her foot bandaged when trailing 4-1 in the second set.

It stalled defeat only briefly, however, as Williams broke her a third time in the set and claimed the match when the Ukrainian sprayed a cross-court forehand wide.

Chasing her 24th Grand Slam title, Williams has conceded only nine games at the tournament and not dropped a set but may finally have a test when she plays the fourth round.

She will face the winner of older sister Venus and top seed Simona Halep for a place in the quarter-finals.

She mentioned Venus was one of the players that left her crying after defeat.

"I remember one time in particular against Venus at Wimbledon, as I was walking to the net, I started bawling," she said. "I couldn't help it. Young girls, young women, just want to go out there and do their best and want to win."

Since returning to the tour after maternity leave, Williams has yet to win a Grand Slam as a mother after two near-misses in the finals at Wimbledon and the US Open.

Seeded 16th in Melbourne, she felt torn about who she might like to play next but said a match against top seed Halep would test her true level.

"Yeah, and I honestly would love to face the world number one," she added.

"At the same time I would love for Venus to win. I think either way, regardless, I'll be ready for either opponent.

"Yeah, it will be great. I haven't played the world number one since I've been back, I don't think. So, yeah, it will be good."