South has capitalised on the withdrawal of Serena Williams
British number four Melanie South made the most of her unexpected opportunity at the East West Bank Classic to reach the third round in Los Angeles.
South beat Czech world number 66 Petra Kvitova 6-4 6-2 in the second round, gaining the upper hand in the first set after initially going a break down.
The 22-year-old lost in qualifying but earned a bye into the second round when Serena Williams withdrew injured.
She will face either 16th seed Sania Mirza or Meng Yuan in the third round.
South, who is ranked 156th in the world, has enjoyed a relatively successful year, winning a tournament in Australia in March then reaching the quarter-finals of the DFS Classic in Birmingham.