Late show at BNP Paribas Open: Sascha Zverev is upset, Naomi Osaka rolls on

Upsets became the norm on Sunday night, as unseeded Joao Sousa of Portugal surprised No. 4 Sascha Zverev of Germany, 7-5, 5-7, 6-4 at Stadium 2 in one of the late-night matches at the Indian Wells Tennis Garden. That added to a string of upsets including the exit of five-time champion Novak Djokovic at the hands of Taro Daniel of Japan, 7-6 (3), 4-6, 6-1 and a surprise victory by 16-year-old Amanda Anisimova over No. 9 seed Petra Kvitova.

Sousa, who is ranked 85th in the world, had been down 1-4 in the third set before he overtook Zverev, who is ranked No. 5 in the world.

In the final women’s match — which ended after 11:30 p.m. PDT — Naomi Osaka of Japan defeated American qualifier Sachia Vickery 6-3, 6-3. Osaka, who had previously defeated Maria Sharapova and Agnieszka Radwanska, advanced to the round of 16 to face unseeded Maria Sakkari of Greece, who had dismissed No 17 seed Coco Vandeweghe 6-2, 6-4.

Juan Martin Del Potro of Argentina, the No. 6 seed, also played in the evening session but he avoided the upset trend with a 6-2, 6-1 victory over 19-year-old Australian Alex de Minaur. No. 2 Marin Cilic of Croatia also moved on after defeating Marton Fucsovics of Hungary 7-5, 6-3.

Osaka gained strength as her match went on. She won the first set when Vickery double faulted, and broke Vickery’s serve early in the second set for a 3-1 lead. Vickery broke back for 3-2 and later broke again for 5-3. Osaka clinched the win on a forehand winner. “The key was trying not to get irritated,” said Osaka, who has spoken before about her need to stay calm and not lose her focus.

She also thanked the remaining fans, who numbered perhaps a few hundred.

Monday looms as another busy and long day, leading off with No. 2 seed Carolina Wozniacki of Denmark facing Aliaksandra Sasnovich of Belarus, and featuring sisters Venus and Serena Williams playing each other in a match that will not begin before 7 p.m.