Naomi Osaka lost in straight sets to qualifier Danielle Collins in the first round of the Abu Dhabi Open.
From 5-4 down in the first set, world No. 71 Collins reeled off nine games in a row to seal a 7-5 6-0 win.
Former world No. 1 Osaka, who has returned to the tour this season after giving birth, went 0-6 on break points.
Osaka has won one of four matches in 2024.
“I still feel like I am in good form even though this is my last year,” said Collins.
“But I needed an end date. I have really enjoyed my time on tour and had a lot of fun, but right now it’s not over yet and I still competing and battling and still have some goals I want to accomplish.”
She added: “I knew what to expect against Naomi.
“She has been out for a while and is still coming back, but I had to lean into my tactics and rely on that and play my game.”
There was little to separate Osaka and Collins in the first set as serve dominated in the opening nine games.
Collins was pushed as she held from deuce for 5-5, and then broke to take the lead.
Osaka saved the first break point with a forehand winner but a netted backhand gave Collins another chance, which she took.
Collins passed up two chances to wrap up the set as she double faulted and missed a backhand.
Osaka fended off a third set point with a winner, but couldn’t prevent Collins taking it at the fourth try.
After such a tight opening set, the second got away from Osaka.
A fortunate net cord helped Collins break to love and she then held from 15-40 down, saving three break points in the game.
Collins broke again for a 3-0 lead as Osaka fired wide.
Again the former world No. 1 had three chances to break back, but couldn’t convert, with a close line call taking Collins to deuce.
Collins took the fifth game with a third successive break and closed out the win with a love hold.