Naomi Osaka's behavior was extremely uncharacteristic, as she is usually composed. Geoff Burke-USA TODAY Sports

Naomi Osaka lost her composure during a third-round upset loss to Leylah Fernandez at the U.S. Open on Friday night. She won the first set and served for the match up 6-5 in the second set but was broken. Then she collapsed in the tiebreaker, committing five unforced errors to lose the set.

Osaka threw her racket after an unforced error down 0-3 in the tiebreaker:

She did it again after losing a point to go down 0-5 in the tiebreaker:

The 23-year-old damaged her racket on three occasions in the match and never received a code violation.

Osaka’s struggles carried into the third set, which she lost 4-6. She was booed by the fans for taking so long between points and for her racket smashes.

Osaka apologized after the match for her racket behavior.

Osaka’s behavior was extremely uncharacteristic, as she is usually composed. Her visible frustration and unsportsmanlike behavior seem to be extensions of the mental issues that have plagued her on the court this year.

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