Rafa Nadal got his usual confidence boost from Nicolas Almagro at Roland Garros, reaching the third round with a 6-4 6-3 6-1 victory - his fourth without dropping a set against his Spanish compatriot on the Paris clay.

Nadal, chasing a record-extending 10th title here, was tested by Almagro, who slumped to 154th in the rankings after a foot injury, but the Mallorcan had just too much strength.

Sixth-seed Nadal, who now has a 68-1 French Open record, wil face either Russian Andrey Kuznetsov or Austrian Juergen Melzer, his semi-final victim in 2010, in the next round.

Meanwhile, Novak Djokovic's hopes of completing a career grand slam by winning the French Open suffered a scare when he needed a medical timeout during a 6-1, 6-4, 6-4 win over Luxembourg's Gilles Muller.

The Serb top-seed slipped on the clay during the second set of the second round match and stretched his right groin muscle, calling for the physio at the change of ends after the ninth game.

The French Open is the only grand slam that Djokovic has not won [Getty Images]

Apart from that it was a straightforward victory as he dropped serve only once.

Elsewhere, Kei Nishikori became the first player through to the fourth round without hitting a ball on Thursday when his third-round opponent Benjamin Becker withdrew injured.

Men's results:

1-Novak Djokovic (Serbia) beat Gilles Muller (Luxembourg) 6-1 6-4 6-4 

17-David Goffin (Belgium) beat Santiago Giraldo (Colombia) 6-3 4-6 7-5 6-2

Andrey Kuznetsov (Russia) beat Jurgen Melzer (Austria) 6-1 5-7 7-6(0) 7-5

6-Rafa Nadal (Spain) beat Nicolas Almagro (Spain) 6-4 6-3 6-1

Thanasi Kokkinakis (Australia) beat 27-Bernard Tomic (Australia) 3-6 3-6 6-3 6-4 8-6

23-Leonardo Mayer (Argentina) beat Jerzy Janowicz (Poland) 6-4 6-4 6-7(1) 6-1

Pablo Andujar (Spain) beat 22-Philipp Kohlschreiber (Germany) 6-1 7-6(5) 3-6 3-6 6-4

9-Marin Cilic (Croatia) beat Andrea Arnaboldi (Italy) 7-6(3) 6-1 6-1

29-Nick Kyrgios (Australia) beat Kyle Edmund (Britain) walkover

Serena surives stern test

The pre-tournament shortlist of favourites for the French Open women's crown continues to shrink and for a while it looked as though the name of top seed Serena Williams would also vanish.

Shortly after former world number one Caroline Wozniacki was knocked out by Julia Goerges, 33-year-old Williams stepped on Court Suzanne Lenglen to face unheralded 21-year-old German Anna-Lena Friedsam.

It looked like a mis-match but 105th-ranked Friedsam gave the 19-time grand slam champion a torrid time, taking the first set off the American before a nervy Williams recovered to scrape into the third round 5-7, 6-3 6-3.

Twice former champion Williams was beaten by Spain's Garbine Muguruza at the same stage last year and more memorably in 2012 when France's Virginie Razzano knocked her out in round one.

Denmark's Wozniacki joined the exodus of women's seeds which includes Romanian third seed Simona Halep, last year's runner-up, and number six Eugenie Bouchard of Canada, losing 6-4 7-6 to Goerges on a blustery Phillipe Chatrier court.

Gorges sent former world number one Wozniacki packing from Roland Garros [Getty Images]

Fourth seed Petra Kvitova survived her own trial, however, coming back to beat Spain's Silvia Soler-Espinosa 6-7, 6-4, 6-2 despite 54 unforced errors.

Women's results:

23-Timea Bacsinszky (Switzerland) beat Tereza Smitkova (Czech Republic) 6-2 6-0 

Tsvetana Pironkova (Bulgaria) beat Denisa Allertova (Czech Republic) 6-3 7-6(2)

16-Madison Keys (U.S.) beat Belinda Bencic (Switzerland) 6-0 6-3

27-Victoria Azarenka (Belarus) beat Lucie Hradecka (Czech Republic) 6-2 6-3

1-Serena Williams (U.S.) beat Anna-Lena Friedsam (Germany) 5-7 6-3 6-3

Andreea Mitu (Romania) beat 12-Karolina Pliskova (Czech Republic) 2-6 7-6(5) 6-4

Francesca Schiavone (Italy) beat 18-Svetlana Kuznetsova (Russia) 6-7(11) 7-5 10-8

30-Irina Begu (Romania) beat Ana Konjuh (Croatia) 6-2 6-0

10-Andrea Petkovic (Germany) beat Lourdes Dominguez Lino (Spain) 4-6 6-4 6-4

4-Petra Kvitova (Czech Republic) beat Silvia Soler Espinosa (Spain) 6-7(4) 6-4 6-2

17-Sara Errani (Italy) beat Carina Witthoeft (Germany) 6-3 4-6 6-2

Julia Goerges (Germany) beat 5-Caroline Wozniacki (Denmark) 6-4 7-6(4)

Irina Falconi (U.S.) beat Sesil Karatantcheva (Bulgaria) 3-6 6-1 6-2

Two-time Wimbledon champion Petra Kvitova needed three sets to beat Spain's Espnosa [Reuters]

Source: Reuters