MELBOURNE, Jan 18, 2025 (BSS/AFP) - Emma Navarro credited her billionaire father for teaching her "toughness" as a child Saturday after she ground past Ons Jabeur into the Australian Open last 16.

The 23-year-old American eighth seed clawed through 6-4, 3-6, 6-4 on Margaret Court Arena, her third straight three-set match.

She will play either Russian ninth seed Daria Kasatkina or Kazakh 24th seed Yulia Putintseva for a place in the quarter-finals.

Navarro has become a three-set specialist with no WTA player playing through more since the beginning of 2024, with the American 23-9 over the distance since then.

"I love three sets. I love tennis so much I can't resist, I gotta play three sets," Navarro joked afterwards.

Daughter of billionaire businessman Ben Navarro, founder of the Sherman Financial Group, she praised her dad, who was courtside, for her stamina.

She recalled how he would take her and her siblings on six-hour bike rides when they were kids.

"We made up a term, biking and crying," Navarro said. "I learned a lot of toughness growing up. A lot of thanks goes to him."

Against Jabeur, she struggled to display the killer instinct, converting only six from 14 break points and being broken six times.

Her frailties were exposed in the first set when she raced 5-0 clear but then imploded, giving up the next four games, but hung on.

She was broken twice again early in set two and again at 5-3 with the Tunisian producing some astonishing drop shots to level the match.

But Jabeur fluffed her chance in set three, squandering three break points in the third game, with Navarro then breaking for 3-2 and rounding out the win.

"I started well but then she played a great four games and a really good second set," Navarro said.

"I just tried to keep working, keep doing my thing and hoping that I would have my chance."