Rafael Nadal has improved his record at Roland Garros to 42-1, beating Ivan Ljubicic 7-5, 6-3, 6-3 to reach the quarterfinals of the French Open.
The five-time champion was not troubled on Court Philippe Chatrier, and the win kept him on course to equal Bjorn Borg's record of six titles on the Parisian clay.
"I have improved since the tournament started," said Nadal, who was pushed to five sets in the first round. "I'm able to play better and I'm going to continue on this path."
Novak Djokovic also had a successful day, even though he wasn't scheduled to play. The second-seeded Serb reached the semifinals of the tournament - where he could meet Roger Federer - when quarterfinal opponent Fabio Fognini withdrew because of injury.
"Walkover from Fognini. Bad luck for him, hope he recovers fast. Today i get to enjoy Paris in a different way :-)" Djokovic wrote on Twitter.
Maria Sharapova also advanced, as did Australian Open runner-up Li Na. Fourth-seeded Andy Murray and Viktor Troicki of Serbia were even at two sets each when their match was suspended because of darkness at 4-6, 4-6, 6-3, 6-2.
Nadal won four straight titles at the French Open before losing to Robin Soderling in the fourth round in 2009. He will face Soderling in the quarterfinals this year after the fifth-seeded Swede defeated Gilles Simon of France 6-2, 6-3, 7-6 (5).
"For me it will be a tough match," Nadal said minutes before Soderling completed his victory. "He's played two finals here at Roland Garros, so he knows what this means. He's got to play his best tennis."
Federer won the 2009 French Open to complete a career Grand Slam, but Nadal returned to win his fifth title in 2010.
Djokovic, who will not be credited with a victory because Fognini withdrew, is after his own records.
If he wins his semifinal match, he would equal John McEnroe's Open era record of 42-0 for the best start to a tennis season and clinch the No 1 ranking. With three more wins, the second-seeded Serb will match the record of 46 straight wins set by Guillermo Vilas in 1977.
The two-time Australian Open champion has never won the title at Roland Garros, but he beat Nadal in two clay-court finals leading up to the French Open.
Fognini, who injured a muscle in his left leg while beating Albert Montanes on Sunday, announced on Monday that he would not be able to play Djokovic, who is 41-0 in 2011 and has won 43 straight matches overall.
"It's better for him," Nadal said of Djokovic's advancement. "He is going to really rest ahead of his semifinal."
Federer will have to beat Gael Monfils to advance to the semifinals. The ninth-seeded Frenchman defeated David Ferrer 6-4, 2-6, 7-5, 1-6, 8-6 in a match that stretched over two days.
"Now I need to recover and at some point I'll stop losing against this Swiss," said Monfils, who has lost five of his six matches against Federer.
Juan Ignacio Chela also reached the quarterfinals. The unseeded Argentine, the only non-European left in the men's draw, beat Alejandro Falla of Colombia 4-6, 6-2, 1-6, 7-6 (5), 6-2.
Sharapova won the last four games to beat 12th-seeded Agnieszka Radwanska of Poland 7-6 (4), 7-5 and reach her first Grand Slam quarterfinal in two years.
The seventh-seeded Sharapova has won the other three major tournaments once apiece, but is still looking for her first title at Roland Garros.
Sharapova will next face 15th-seeded Andrea Petkovic of Germany, who defeated No 25 Maria Kirilenko of Russia 6-2, 2-6, 6-4.
The sixth-seeded Li became the first Chinese player to reach the quarterfinals at Roland Garros by beating No 9 Petra Kvitova of the Czech Republic 2-6, 6-1, 6-3. She will next face No 4 Victoria Azarenka of Belarus, who beat Ekaterina Makarova of Russia 6-2, 6-3.
"I was really in trouble," Li said about trailing 3-0 in the third set. "I didn't believe I could come back, because she has a huge big serve. But I was OK. She had just broken once."
