In an all-American fourth-round affair on Melbourne Arena, Kenin kept her cool to overturn a set deficit and score a 6-7 (5-7) 6-3 6-0 victory on Sunday over the teen sensation.

The 21-year-old, who won three WTA titles last year, was unable to contain her emotions following the breakthrough three-set triumph.

"It was such a tough match," Kenin said.

"It means a lot to me. I'm so happy to be through to the next round."

At the tender age of 15, Gauff has been the talk of the tournament at Melbourne Park after claiming the scalps of defending champion Naomi Osaka and seven-time major winner Venus Williams.

She's projected to rise to a career-high ranking of world No.52 when the latest WTA rankings are released.

"She's such a tough player," said Kenin, the tournament's 14th seed.

"(She's) had a tremendous 2019 and started off really well.

"All respect to her. She played a really great match."

Moscow-born Kenin raced out to a 4-2 lead in the first set before Gauff clawed her way back to prevail in a tiebreak.

But the teen wunderkind then went slightly off the boil, racking up 14 unforced errors as Kenin levelled the match at a set apiece.

Carrying the momentum, Kenin drew first blood in the deciding set and did not look back.

Having never been past the fourth round of the major until now, Kenin will have a golden chance to push on to the semi-finals with victory over world No.78 Ons Jabeur.

The Tunisian surprise packet was too good for Serena Williams' slayer Qiang Wang, enduring a tough first set before streaking to a 7-6 (7-4) 6-1 win.

Earlier, Czech champion Petra Kvitova fought back from a set down to beat Greek 22nd seed Maria Sakkari 6-7 (4-7) 6-3 6-2 on Rod Laver Arena.

The two-time Wimbledon champion was staring down the barrel early in the second, down a set and a break to the 22nd seed.

But her experience shone through from that point onwards in the fourth-round clash, winning 11 of the next 15 games to reach the last-eight at a grand slam for a 12th time.

Beaten in their past two meetings at Cincinnati and Rome last year, Kvitova was under no illusion that stopping the 24-year-old - the first Greek woman to reach the last 16 at a major since 2005 - would prove a hard task.

"It's really tough to play Maria," she said.

"Last time I lost to her, so I really knew it would be a difficult match."

Kvitova will play top seed Ashleigh Barty after the Australian downed Alison Riske 6-3 1-6 6-4 in their round of 16 clash.

Australian Associated Press