Paris - Defending champion Maria Sharapova reached the French Open fourth round on Saturday with a 6-1, 7-5 win over China's Zheng Jie despite an up and down centre court performance.
The second seeded Russian will take on America's Sloane Stephens, who she beat comfortably on clay in Rome two weeks ago, for a place in the quarter-finals.
But the 26-year-old Russian has work to do ahead of that encounter after dropping serve four times against Zheng and serving up eight double faults.
The pain of her 34 unforced errors was at least partially soothed by her 25 winners.
"I was lucky to get through that second set. I was a break down so I am happy to pull it through in straight sets," she said.
"It's not over until the last point is played and I felt like I was playing with a lot of energy out there."
Sharapova, playing in her 11th French Open, had reached the third round for the loss of just nine games and seemed on course for another routine win on Saturday.
Four breaks of serve helped her to the first set as her 43rd-ranked opponent failed to hold serve once while winning only nine points off the Russian's serve.
However, two breaks took the 29-year-old from Chengdu out to a 4-1 lead in the second before Sharapova turned up the heat again.
The champion pulled level at 4-4, pumping up the volume levels at the same time, only to hand Zheng the initiative again as the Chinese player broke for 5-4.
Zheng, who became the first Chinese woman to make the last 16 of a major when she played in the fourth round in Paris in 2004, was unable to serve out the set as Sharapova broke for 5-5.
The world number two held for 6-5 and took the tie after 1hr 45min when Zheng netted a return.
French Open results on Saturday (x denotes seeded player):
Novak Djokovic (SRB x1) bt Grigor Dimitrov (BUL x26) 6-2, 6-2, 6-3
Philipp Kohlschreiber (GER x16) bt Victor Hanescu (ROM) 6-0, 7-6 (7/0), 6-1
Tommy Haas (GER x12) bt John Isner (USA x19) 7-5, 7-6 (7/4), 4-6, 6-7 (10/12), 10-8
Mikhail Youzhny (RUS x29) bt Janko Tipsarevic (SRB x8) 6-4, 6-4, 6-3
Rafael Nadal (ESP x3) bt Fabio Fognini (ITA x27) 7-6 (7/5), 6-4, 6-4
Kei Nishikori (JPN x13) bt Benot Paire (FRA x24) 6-3, 6-7 (3/7), 6-4, 6-1
Stanislas Wawrinka (SUI x9) bt Jerzy Janowicz (POL x21) 6-3, 6-7 (2/7), 6-3, 6-3
Richard Gasquet (FRA x7) bt Nikolay Davydenko (RUS) 6-4, 6-4, 6-3
Bethanie Mattek-Sands (USA) bt Paula Ormaechea (ARG) 4-6, 6-1, 6-3
Maria Kirilenko (RUS x12) bt Stefanie Voegele (SUI) 7-6 (7/3), 7-5
Francesca Schiavone (ITA) bt Marion Bartoli (FRA x13) 6-2, 6-1
Victoria Azarenka (BLR x3) bt Alize Cornet (FRA/N.31) 4-6, 6-3, 6-1
Jamie Hampton (USA) bt Petra Kvitova (CZE x7) 6-1, 7-6 (9/7)
Jelena Jankovic (SRB x18) bt Samantha Stosur (AUS x9) 3-6, 6-3, 6-4
Sloane Stephens (USA x17) bt Marina Erakovic (NZL) 6-4, 6-7 (5/7), 6-3
Maria Sharapova (RUS x2) bt Zheng Jie (CHN) 6-1, 7-5