Life as world No 1 got off to a losing start for Naomi Osaka as she crashed out of the Dubai Duty Free Tennis Championships on Tuesday night.
The Japanese player was playing for the first time since she reached top spot by winning the Australian Open in January, but she looked badly out of sorts as she was beaten 6-3, 6-3 by Kristina Mladenovic.
Osaka was broken seven times in the match, three of those being in the first set, as she struggled to get any kind of consistency to her game.
Osaka had beaten Mladenovic, the world No 64, in straight sets at the same stage 12 months ago, making the loss so surprising.
Mladenovic now faces Carla Syarez Navarro for a place in the quarter-finals on Wednesday.
Kerber survives scare to win
Angelique Kerber bounced back from being 5-1 down in the first set to Dalila Jakupovic to win 7-6, 6-3 in her second-round match at the Dubai Duty Free Tennis Championships.
The Wimbledon champion was broken twice as she seemed to struggle to get to grips with her Slovakian opponent.
But she hit back with four games in a row to get the match on serve.
The German, who is a three-time major winner, was then broken for a third time in the set, but broke straight back to force a tie-break, which she won 7-4.
Kerber dominated the second set and after failing to convert break points in Jakupovic's first three service games she broke in the seventh and ninth games to seal victory.
Halep quells Bouchard challenge
Simona Halep overcame the challenge of a spirited Eugenie Bouchard to reach the last 16 of the Dubai Duty Free Tennis Championships.
The world No 2 prevailed 7-6, 6-4 over the Canadian on Centre Court to set up a match with either Lesia Tsurenko or Yulia Putintseva on Wednesday for a place in the quarter-finals.
Halep had looked as if she had taken control of the match when she broke to go 4-2 up in the first set.
But former world No 5 Bouchard, who is now down to No 79 in the world, hit back in the next game with some fine returns to break straight back.
Halep though won the tie-break 7-3 and then she broke Bouchard in the opening game of the second set, and that proved to be the only break of the set as the Romanian clinched victory in straight sets.
Svitolina through after Jabeur injury
Elina Svitolina, the defending champion at the Dubai Duty Free Tennis Championships, is through to the last 16 after opponent Ons Jabeur retired hurt with what appeared to be a shoulder injury.
Svitolina, bidding to be the first woman to win the Dubai title three times in a row, had made a poor start and was broken in her first service game.
She was 4-1 down before winning four games on the trot to put herself in position to win the set.
But Tunisian Jabeur broke back and led 6-5 before hurting herself and requiring extensive treatment on court, with her right shoulder and arm being massaged.
She returned to court but lost the first set on the tie-break and had lost every game of the second set before she called it quits and shook hands with Svitolina at the net with the score at 7-6, 4-0.
Svitolina will play the winner of the match between 12th seed Garbine Muguruza and Saisai Zheng for a place in the quarter-finals on Wednesday.
Kvitova makes slow start
Petra Kvitova overcame a slow start to book her place in the last 16.
The world No 3 looked out of sorts initially against Czech compatriot Katerina Siniakova and had her serve broken twice.
She dropped the first set but hit back to claim the final two sets to prevail 6-7, 6-4, 6-4 in a gruelling encounter that lasted two hours and 35 minutes.
The 2013 Dubai winner will go up against either 14th seed Caroline Garcia or Jennifer Brady on Wednesday for a place in the quarter-finals.
Meanwhile, Daria Kasatkina's hopes of repeating her run to the final in Dubai are over after she was beaten in the second round.
The Russian 11th seed, who was the surprise package of the 2018 competition before losing to Elina Svitolina in the championship game, went down 6-3, 2-6, 6-4 to world No 36 Sofia Kenin in the opening match of the day.
Another surprise exit was world No 8 Kiki Bertens, who lost to Viktoria Kuzmova 6-2, 4-6, 7-6 in the opening match on Court 1.