ABU DHABI, U.A.E. -- No.9 seed Maria Sakkari of Greece booked her spot in the quarterfinals of the Abu Dhabi WTA Women's Tennis Open on Sunday, ousting No.5 seed Garbiñe Muguruza of Spain, 7-5, 6-4.

"Overall, I think I’m starting to feel like I want to feel in the season, during the tournaments, playing-wise," said Sakkari, during her post-match press conference. "So I’m feeling good."

"I just see moments of the match and feel like I’m getting there, even though it’s the first tournament," Sakkari added. "I’m super happy that I can play this way, because other years I was struggling a lot in the first couple of weeks. Slowly, slowly, I’m feeling some things from my off-season."

World No.22 Sakkari earned her 17th career win over a Top 20 opponent with her one-hour and 51-minute victory over 15th-ranked Muguruza. The Greek has slid into the final eight of the season-opening event without having dropped a set in her three victories.

In the first meeting between the two players, Sakkari was the aggressor, firing 33 winners, including 11 aces, and converting three of her nine break points. By contrast, former World No.1 Muguruza could muster up just five winners in the match, and had only ten fewer unforced errors than Sakkari.

"I think I was in trouble a lot of times during the match -- when I say trouble, I mean break points down -- and I think I came up with some good serves a few times when I needed them," sad Sakkari.

Sakkari found herself in dire straits early, staring down two break points at 2-1 after two double faults, but the Greek powered her way back to game point with three consecutive winners, and held on for 2-2. Sakkari was rewarded for her persistence, slamming strong groundstrokes and deep returns to claim a love break and move ahead 4-3.

After saving two more break points to consolidate for 5-3, Sakkari held five set points in the lengthy next game. It was here where the championship experience of Muguruza made a difference, as the Spaniard stayed steely and fended off the entirety of the quintet with patience and grit.

Once out of that jam, Muguruza clawed back to parity, drawing errors from the racquet of Sakkari to reach 5-5. However, Sakkari continued to play aggressively, finding winners more often than not, and fired a forehand square on the sideline to convert another break point and reclaim her break advantage at 6-5.

In the following game, Sakkari’s fifth ace of the set brought her three more set points, and this time around, the Greek would make no mistake, polishing off the set on her seventh chance with yet another forehand winner.

In the second set, Sakkari again had to come through an early-set predicament at 2-1, where she was forced to stare down five break points. The Greek, to her credit, came up with strong serves to wipe many of those chances away, and she once more held firm for 2-2.

Just like in the first set, Sakkari took her big chance at 3-3, where she pulled through one of the many close games to earn the break with an angled dropshot winner. The Greek powered her way to a hold for 5-3, closing out that game with a backhand crosscourt winner and putting herself a game away from another Top 20 victory.

Serving for the match at 5-4, Sakkari nearly continued the carbon copy of the opening frame, as she faced three break points. However, the serve dug the Greek out of trouble once more, as stellar deliveries erased all of Muguruza’s chances in that game. Sakkari at last advanced to match point, which she converted with her 11th ace of the day.

For her quarterfinal opponent, Sakkari will face No.1 seed Sofia Kenin of the United States, who had to save a match point before beating No.13 seed Yulia Putintseva of Kazakhstan on Sunday. Kenin leads the head-to-head with Sakkari by 2-0, but they have not played each other since the 2018 US Open.

2021 Abu Dhabi Highlights: Sakkari ousts Gauff