Naomi Osaka’s first match since her Australian Open triumph didn’t quite go to plan, falling to an inspired Kristina Mladenovic in straight sets at the Dubai Duty Free Tennis Championships.

DUBAI, UAE - France’s Kristina Mladenovic pulled off a stunning upset at the Dubai Duty Free Tennis Championships, taking down World No.1 Naomi Osaka in straight sets to reach the round of 16.

Coming into her first match since her Australian Open triumph, Osaka was also entering the Emirati event without coach Sascha Bajin at her side after the two suddenly parted ways last week. Questions swirled about her form and mentality as she took the court against the No.67-ranked Mladenovic.

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For her part, Mladenovic claimed her first main draw win of the year here in Dubai, ending her four-match losing streak against Omani wildcard Fatma Al-Nabhani in the first round.

A former Top 10 player, Mladenovic was undaunted by the two-time Grand Slam champion and World No.1 Osaka across the net. She played inspired, focused tennis, needing just 67 minutes to win 6-3, 6-3 - and claim the biggest win-by-ranking of her career.

The Japanese player was sluggish from the start, her usually-powerful groundstrokes not hitting their mark as a dialled-in Mladenovic took her chance to strike first. She edged through a tough battle to start the first game with a break, and then dodged two break back points to extend her lead to 2-0.

Another break to love put Osaka down a daunting 3-0 - but this time, the double break deficit seemed to jolt the Japanese player back to life. She looked to be finally finding her range, getting the break straight back and then cutting down Mladenovic’s advantage to 3-2.

But although Osaka kept pushing and keeping the Frenchwoman under pressure, Mladenovic held up under the World No.1’s scrutiny. She regularly charged to the net, breaking up the rhythm of the rallies and employing her doubles skills to great success. An ill-timed double fault from Osaka - one of five in the match - gave Mladenovic another break at 6-3 to take the opening set.

Mladenovic started out the second set with a strong hold of serve - a hold that would later prove decisive in light of the seven consecutive breaks of serve that followed.

Osaka and Mladenovic were toe to toe for the majority of the second set - Mladenovic quickly built up a 2-0 lead but Osaka made sure to stay within touching distance and broke straight back. But Osaka was always one step behind the Frenchwoman, and never managed to hold her serve against Mladenovic’s relentless attack. Mladenovic served out the set - and the match - to claim her spot in the third round after 67 minutes on court.

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In the end it was Osaka’s unforced error count that was her undoing: she hit 19 winners against Mladenovic’s 16, but they were offset by 25 unforced errors while Mladenovic kept her count contained to just nine.

Up next, Mladenovic will face former Qatar champion Carla Suarez Navarro for a spot in the Dubai quarterfinals. The Spaniard edged past Zhang Shuai 6-4, 6-4 earlier in the day to advance.

More to follow...