Fourth seed Elena Dementieva avoided an embarrassing early exit when comeback queen Jelena Dokic's French Open hopes were ended by a back injury on Thursday.



Jelena Dokic was left in tears after being forced to retire hurt against Elena Dementieva at the French Open.



Dokic, taking part in her first French Open since 2004 following well-documented family problems, won the first set 6-2 and -- after her first break for treatment -- broke the 2004 finalist to lead 3-2 in their second round clash.



But the Russian won the next two games as the tearful former world No.4 was reduced to walking pace before calling it quits.



"I went for a return and I just went down and couldn't get back up," she said. "It's very painful and very disappointing because I felt as if I had the match in my hands."



Dokic, now ranked 80th after reviving her career with a run to the quarter-finals of the Australian Open in January, had won her opening match on Tuesday when she came back from a set down to beat Slovenia's Karolina Sprem 3-6 6-1 6-2.



The 26-year-old's career had nosedived following her highly-publicized split from controversial mentor and father Damir.



Dementieva will next play Australian 30th seed Samantha Stosur, who won her second-round match in straight sets against Belgium's Yanina Wickmayer.



Earlier on Thursday, the Williams sisters also progressed through to the third round with contrasting victories.



Second seed Serena crushed Virginia Ruano Pascual 6-2 6-0 to set up a clash with another unseeded Spaniard, Maria Jose Martinez Sanchez.



Third seed Venus survived a scare against unseeded Czech Lucie Safarova before completing a match that was halted on Wednesday night due to bad light.



The American saved a match point at 5-4 down in the third set before managing to hold, break her opponent and then serve out to love for a 6-7 (5-7) 6-2 7-5 success.



Venus, who lost the 2002 final to Serena, will next play Hungarian 29th seed Agnes Szavay.



Fifth seed Jelena Jankovic had no such troubles in beating Magdalena Rybarikova of Slovakia 6-1 6-2, setting up a third-round clash with unseeded Austrian Jarmila Groth.



Seventh-seeded Russian Svetlana Kuznetsova also advanced along with Danish 10th seed Caroline Wozniacki, but 13th seed Marion Bartoli of France made a surprise exit.



The 2007 Wimbledon finalist lost 6-3 7-5 to Tathiana Garbin of Italy, who will next take on unseeded Virginie Razzano of France.
What ranking was Dokic? What ended Dokic's comeback? How far did she lead by? What world ranking did she have? When did Dokic get injured? When did she call it quits? When did she quit? Did Jelena Dokic's comeback end?
ranked 80th a back injury 3-2 in their second round clash. No.4 Thursday. Thursday. Thursday. ended by a back injury on Thursday.
question: What ranking was Dokic?, answer: ranked 80th | question: What ended Dokic's comeback?, answer: a back injury | question: How far did she lead by?, answer: 3-2 in their second round clash. | question: What world ranking did she have?, answer: No.4 | question: When did Dokic get injured?, answer: Thursday. | question: When did she call it quits?, answer: Thursday. | question: When did she quit?, answer: Thursday. | question: Did Jelena Dokic's comeback end?, answer: ended by a back injury on Thursday.