World number two Iga Swiatek and Australian Open champion Elena Rybakina both crashed out of the Qatar Open on Thursday losing their quarter-finals to Maria Sakkari and Victoria Mboko respectively.

Top seed Swiatek fell short against a revitalised Sakkari who rolled back the years as she clawed her way to a nervy 2-6, 6-4, 7-5 victory while 10th seed Mboko outmuscled Rybakina 7-5, 4-6, 6-4.

"It's been a while since I had a big win like today," said Sakkari, who reached No. 3 in the rankings in 2022 but has slipped to 52nd.

"When you drop in the rankings and you're not playing good tennis you start doubting yourself and you think you are never going to beat those players again.

"So it's a huge process you have to go through in your head that you can do it."

The 30-year-old Greek won her first three career meetings with the young Swiatek but the last of those victories came in 2021.

The Pole had won their last four matches, the most recent in straight sets in Qatar last year.

"Last year in the second round here against her, I was not confident, I was not believing in myself and this year it's different. I feel a lot better," said Sakkari who will now face either 14th seeded Czech Karolina Muchova or unseeded Russian Anna Kalinskaya,.

"I've missed that feeling of going deep into tournaments."

Swiatek, who won the Qatar tournament, a WTA 1000 event, in 2022, 2023 and 2024, started as if she would repeat last year's rout when she broke twice in the first set.

Sakkari began to fight back in the last game, but Swiatek saved a break point to seal the set.

Sakkari continued her upswing by breaking in the second game of the second set.

Yet every time she gained an edge, Swiatek responded. The Pole broke in the seventh game, but Sakkari steadied and broke in the tenth game to take the set.

It was the first time in their seven meetings that a match between the pair had gone to a third set.

In a see-saw deciding set, Swiatek saved a match point on her serve before Sakkari held to love, the Greek going on to win in the next game, on her third match point. (AFP)