Naomi Osaka was brought to tears by a heckling spectator during her Indian Wells Open match with Veronika Kudermetova before going on to lose 6-0 6-4.

The incident happened after Osaka had been broken by Kudermetova in the first game, with someone in attendance reported to have yelled "Naomi, you suck".

Four-time grand slam winner Osaka, competing in her first tournament since January's shock early Australian Open exit, appeared to ask the chair umpire to take action.

Osaka initially put that unneeded distraction behind her by taking the next point, but she wasted two break opportunities and Kudermetova successfully held to move 2-0 ahead.

The 24-year-old was in tears as she prepared to serve her next game and held further discussions with the court supervisor after going 3-0 down.

She could not recover and, after losing the first set 6-0, Osaka suffered the only break of serve in the seventh game of the second set to lose the contest fairly resoundingly. 

Kudermetova will now face Marie Bouzkova for a place in the last 16 after the Czech recovered to see off home hopeful Jessica Pegula 5-7 6-2 6-0.

Two-time champion Victoria Azarenka also made it through on Saturday with a 6-3 7-5 victory over lucky loser Astra Sharma, setting up a meeting with Elena Rybakina.

Leyla Fernandez saved four match points against Amanda Anisimova in a dramatic match that came to an end when the American retired through illness.

After losing the opener 6-2, Fernandez took the second set to a tie-break but felt unable to continue. Anisimova will meet Shelby Rogers in a rematch of last year's last-16 encounter.