Zheng Saisai caused the first major upset at the Qatar Total Open when she knocked out top seed Angelique Kerber before Elena Vesnina followed suit by defeating second seeded Simona Halep.
World number 73 Zheng played well above her lowly ranking to stun the recently crowned Australian Open champion, 7-5, 6-1, in an hour and 20 minutes.
Zheng varied her play to great effect as 11 of her 17 winners came at the net.
“She’s unbelievable at running so the only way I could win the point sometimes was by coming to the net,” the Chinese player said after her match.
In the third round she will face Eugenie Bouchard who overcame Denisa Allertová 7-6 (0), 7-5.
In the days other major upset, Vesnina scored one of the biggest wins of her career over Halep when she triumphed 6-7(1), 6-4, 6-1.
Seemingly down and all but out of the match with the world number four up a set and a double break in the second stanza, Vesnina was somehow still able to grind out a comeback victory that no superlative can do justice.
“That’s my character, I’m always fighting ’til the end,” she said.
“I was thinking, ‘I’m on center court here in Doha, I’m playing Simona, 1-4 down but it doesn’t matter.
“I just fight game by game, ball by ball, and it just worked.”
The Russian qualifier will square up with Caroline Wozniacki next after she beat Daria Gavrilova 6-3, 6-3.
Elsewhere there were comprehensive straight set wins for Agnieszka Radwanska, Andrea Petkovic, Carla Suárez Navarro, Petra Kvitová, Tímea Babos, Timea Bacsinszky, Jelena Ostapenko, Coco Vandeweghe, Cagla Buyukakcay and Garbiñe Muguruza.
While Roberta Vinci and Monica Niculescu were two of only three players on Tuesday who were forced to go to three sets before progressing to the last 16.