In the first match of the tournament on Stadium, Heather Watson rallied from 0-5 third set to win.
Another teenager, American Sloane Stephens, rallied from a set down to win her first two matches.
Alisa Kleybanova made a winning return from battling Hodgkin's lymphoma, defeating Johanna Larsson.
Alisa Kleybanova was presented with a cake and flowers to commemorate her return to the courts.
Venus Williams also made a triumphant return from illness, beating Kimiko Date-Krumm first round.
Iveta Benesova saved match points to edge former Miami champion Svetlana Kuznetsova, 16 76(7) 76(7).
Aleksandra Wozniak beat Monica Niculescu in the second round to set up a clash with Venus Williams.
Shahar Peer had never beaten Maria Sharapova in five tries, but never came closer than in Miami.
Maria Sharapova battled nearly two and a half hours to survive Shahar Peer on Friday, 46 63 63.
After a miracle comeback in the first round, Heather Watson routed No.27 seed Lucie Safarova, 62 61.
No.11 seed Francesca Schiavone looked headed for a three set win, building a 3-0 lead in the decider.
But Ksenia Pervak scored her third Top 20 win of the year, beating Francesca Schiavone, 64 46 75.
Victoria Azarenka improved to 24-0 with a 63 75 win over Michaella Krajicek in the second round.
In her first WTA event since the US Open, Venus Williams stunned Petra Kvitova in the second round.
Venus Williams' 64 46 60 win over World No.3 Petra Kvitova lit up the Miami crowds Friday night.