Serena ##erer beat turkey 's Zarina Diyas 6 - 2 , 6 - 0 on Sunday . Williams was impressive in qualifying but says she ' can do a lot better ' The fed No rankings will play fellow American Sloane ##yas in fourth round .
Serena Williams beat Kazakhstan 's Zarina Diyas 6-2 , 6-0 on Sunday . Williams was impressive in victory but says she 'can do a lot better ' The world No 1 will play fellow American Sloane Stephens in fourth round .