Kazakhstan's Yaroslava Shvedova beat former French Open champion Francesca Schiavone 6-4 6-2 at the Sony Open on Tuesday, earning a second-round meeting with world number one Serena Williams.
The world number 59 broke the Italian to take the first set and broke again to move ahead 3-1 in the second before recording one final break to close out the contest and collect her first win in four meetings with the 2010 French Open champion.
Schiavone, the first Italian woman to win a grand slam, has been in miserable form losing seven consecutive first-round matches before ending the barren stretch last week at the BNP Paribas Open in Indian Wells.
Shvedova, whose only career WTA Tour win came seven years ago in Bangalore, has lost all three meetings with Williams but did push the six-times Miami champion to three sets during a round of 16 meeting at the 2012 Wimbledon.
The upset of the day went to 20-year-old Monica Puig who dispatched 36th ranked Magdalena Rybarikova of Slovakia, a four-time winner on the WTA Tour, 6-1 7-6 (9-7).
It was the second match win of the season for the 58th ranked Puerto Rican.
The tournament began on a down note for the home contingent with American Bethanie Mattek-Sands falling 6-3 3-6 6-3 to Ukraine's Elina Svitolina.