Paris, France (SportsNetwork.com) - Reigning world No. 1 Novak Djokovic, surging Andy Murray and nine-time champion Rafael Nadal were a trio of second- round winners Thursday at the French Open.

The two-time runner-up Djokovic straight-setted Luxembourg left-hander Gilles Muller 6-1, 6-4, 6-4, but the Serbian star did require a medical timeout on Day 5 to loosen up the left side of his body.

The eight-time Grand Slam champion Djokovic extended his current winning streak to 24 matches.

The reigning Australian Open and Wimbledon champ needs a French Open title to complete a career Grand Slam. He lost to Nadal in last year's final and in the 2012 championship match.

Up next for Djokovic will be promising 19-year-old Aussie Thanasi Kokkinakis.

The third-seeded Murray improved to 12-0 on clay this year by holding off capable Portuguese Joao Sousa 6-2, 4-6, 6-4, 6-1. The 26-year-old Sousa was bidding to become the first Portuguese man in history to reach the third round at Roland Garros.

The two-time Grand Slam champion Murray was this year's Aussie Open runner-up to Djokovic. The British star is a two-time French Open semifinalist, including last year.

His third-round opponent will be 29th-seeded Aussie slugger Nick Kyrgios, who received a walkover into the round of 32 on Wednesday.

The former world No. 1 Nadal, seeded sixth at this particular fortnight, blew away fellow Spaniard Nicolas Almagro 6-4, 6-3, 6-1 on Court Chatrier.

"I'm very happy," said Nadal. "I think I played a good match. The score is easier than what the match was like. I think I did a few things very well.

"My footwork was better. I felt better than during the first round. I'm very happy with my performance and result."

The 14-time Grand Slam champion Nadal has now won his last 37 matches at Roland Garros, where he's won the last five titles. He captured four straight French Open titles from 2005-08.

Nadal's trying to become the first man to win 10 titles at one major tournament.

His third-round opponent will be Russian Andrey Kuznetsov.

Seventh-seeded 2013 French Open runner-up David Ferrer whipped fellow Spaniard Daniel Gimeno-Traver 6-3, 6-2, 6-1, while ninth-seeded U.S. Open champion Marin Cilic reached the third round by handling Italian Andrea Arnaboldi 7-6 (7-3), 6-1, 6-1. Ferrer will face Italian Simone Bolelli on Saturday, while Cilic's next opponent will be in-form Argentine Leonardo Mayer.

Fifteenth-seeded South African Kevin Anderson overcame Taiwan's Yen-Hsun Lu 5-7, 6-4, 6-4, 6-4; France's Jeremy Chardy upset 16th-seeded American John Isner 6-4, 4-6, 6-3, 6-3; quality 17th-seeded Belgian David Goffin moved on by defeating Colombian Santiago Giraldo 6-3, 4-6, 7-5, 6-2; and 18-year-old blossoming star Borna Coric of Croatia took out 18th-seeded Spaniard Tommy Robredo 7-5, 3-6, 6-2, 4-6, 6-4.

In other second-round action involving seeds, Spaniard Pablo Andujar upended No. 22 German Philipp Kohlschreiber 6-1, 7-6 (7-5), 3-6, 3-6, 6-4; a No. 23 Mayer topped Poland's Jerzy Janowicz 6-4, 6-4, 6-7 (1-7), 6-1; the aforementioned Kokkinakis saved three match points in tripping up No. 27 fellow countryman Bernard Tomic 3-6, 3-6, 6-3, 6-4, 8-6; and Bolelli dismissed No. 31 Serb Viktor Troicki 6-2, 6-4, 6-3. Mayer was a clay-court runner-up in Nice last week.

Also on Thursday, surprising American Jack Sock overcame Spaniard Pablo Carreno Busta 6-7 (2-7), 7-6 (7-4), 6-1, 7-6 (7-4) and Kuznetsov bested Austrian veteran Jurgen Melzer 6-1, 5-7 (7-0), 7-6, 7-5. Sock will encounter the talented Coric in the round of 32.

Frenchman Richard Gasquet, seeded 20th, was tied with Argentine Carlos Berlocq 3-6, 6-3, 6-1, 4-6 when play was suspended because of darkness.

And thanks to his next opponent's withdrawal, Japan's Kei Nishikori became the first player to reach the second week of the French Open.

The fifth-seeded U.S. Open runner-up was supposed to play Benjamin Becker in the third round on Friday, but the German Becker pulled out of the tournament because of a muscle tear in his right shoulder.

That puts Nishikori in the fourth round at Roland Garros for the second time. In 2013, he became the first man from Japan to make it that far in 75 years.

Next for Nishikori will be a fourth-round match on Sunday against Czech Lukas Rosol or Russian Teymuraz Gabashvili.

On Friday, former French Open champion and four-time runner-up Roger Federer will face Bosnian Damir Dzumhur in the third round.

The 17-time Grand Slam king Federer was last year's Wimbledon runner-up to Djokovic.

In other third-round action involving Top-10 seeds on Day 6, No. 4 former Wimbledon runner-up Tomas Berdych will take on France's Benoit Paire and No. 8 former Aussie Open champ Stan Wawrinka will battle two-time NCAA singles champion Steve Johnson of the United States.

Also seeing action on Friday will be seeded French favorites, No. 12 Gilles Simon, No. 13 Gael Monfils and former Aussie Open finalist, No. 14 Jo-Wilfried Tsonga.