Reigning Australian Open champion Aryna Sabalenka suffered an opening round upset at the hands of familiar foe Donna Vekic, going down 6-7 (5/7), 6-3, 6-0 in Dubai on Tuesday.

Contesting her first match since her successful title defence at Melbourne Park, Sabalenka blew a 7-6, 2-0 lead to succumb to her Croatian opponent in two hours and 22 minutes.

The 31st-ranked Vekic, who now owns a 6-2 head-to-head lead in lifetime meetings against Sabalenka, was aggressive throughout the match and enters her next clash with big-hitting Romanian Sorana Cirstea searching for her first WTA 1000 quarter-final of her career.

“At all times I didn’t give up. I didn’t stop believing that I can win. I just kept fighting,” said Vekic, who is 9-13 against top-five opposition.

“To be honest, I didn’t have big expectations coming to Dubai. Told my coach that I’m taking this week as half holidays. I can tell you I spent more time on the beach than on the court. Maybe that’s a good way going forward,” she added with a laugh.

In windy but warm conditions in Dubai, Sabalenka recovered from a break down then squandered a 5-3 lead before securing the opening set on her sixth opportunity on the 69-minute mark.

The world number two leapt to a 2-0 advantage in the second set but Vekic struck back and claimed another crucial break in game eight to level the contest and force a decider.

With the wind in her sails, Vekic put together a nine-game winning run, outhitting her powerful opponent, to deliver a final-set bagel and book her place in the last 16.

Earlier on Centre Court, eighth seed Maria Sakkari snapped a three-match losing streak and claimed her first-ever Dubai main-draw victory, on her fourth attempt, with a 6-2 6-4 triumph over in-form American Emma Navarro.

After suffering opening round exits in Abu Dhabi and Doha, Sakkari was admittedly nervous ahead of her clash with Navarro, who is already a title-winner in 2024 and has amassed 13 victories in the first two months of the season.

“It was very tough. Last night I couldn’t sleep just because I was overthinking about it and it wasn’t easy. No one wants to keep losing first round. But I told myself to treat it as the first match of the season. Obviously it wasn’t my best, best tennis but it was good enough to beat a top-form player,” said Sakkari, who faces Leylah Fernandez or Jasmine Paolini next.

Sakkari is in search of a new coach having ended her six-year partnership with Tom Hill. The Greek world number 11 briefly worked with Sergi Bruguera during the offseason and after the Australian Open but needs to find a full-time coach given Bruguera’s commitment to ATP player Arthur Fils. She is confident she will have found a new coach by the time Indian Wells commences next month.

Speaking of her split with Hill, Sakkari said: “It was very tough. I just felt like we couldn’t really help each other, we couldn’t move forward but we remain very, very good friends, that’s never going to change.”

In Dubai, Sakkari is joined by her mother Angeliki, who is a former top-50 WTA player, and her hitting partner Julien Cagnina.

“She’s my emergency coach, that’s what I call her,” said Sakkari of her mother. “It’s nice to have her, we’ve been going out for dinners every day, it’s been a very relaxing week with them.”