Peng will next play the Czech Republic's Iveta Benesova, who beat Rezai's fellow Frenchwoman Mathilde Johansson 6-3 2-6 6-4.

CNN: No. 1 Wozniacki wins Melbourne opener

Jo-Wilfried Tsonga beat John Isner 6-3 6-2 to put France ahead before Williams fought off Mathilde Johansson 3-6 7-5 6-4 to draw the U.S. level.

CNN: Injured Sharapova pulls out of season opening tournament

Stephens' 6-3 6-2 win against France's Mathilde Johansson meant the 70th-ranked 19-year-old reached the fourth round of a grand slam for the first time in her career.

CNN: STORY HIGHLIGHTS

Jo-Wilfried Tsonga put France ahead as he beat Fernando Verdasco 7-5 6-3, but Anabel Medina Garrigues leveled it for Spain with a 6-3 6-2 win over Mathilde Johansson.

CNN: STORY HIGHLIGHTS