Osaka was exposed during the match against Veronika Kudermetova, fell in two straight sets with 6-0, 6-4 and could later be seen wiping tears from her eyes.
Afterwards, she told the center court that the incident reminded her of the double mockery of sisters Serena and Venus Williams in 2001.
The Japanese has struggled with mental illness and took a timeout from the sport after the loss in last year's US Open.
But now she is back and there were other tones from the audience when she beat the Australian Astra Sharma 6-3, 6-4.