Paris - Rafael Nadal shrugged off another bout of back pain to charge into the last 16 of the French Open with an imposing 6-2, 7-5, 6-2 win over Leonardo Mayer of Argentina.
Seeking to become the first man to win five straight titles in Paris and the first to win nine times at the same Grand Slam, Nadal has lost just 19 games in getting to the last 16.
At the same stage last year en route to his eighth French Open title, Nadal had dropped two sets and lost 48 games.
Mayer, ranked 65th in the world, had little to offer as Nadal led from the start and was able to play well within his limits and still race away with the match.
The only blip came in the eighth game of the second set when Mayer broke for the first time in the match to level at 4-4.
But minutes later Nadal snuffed out any nascent threat to go two sets clear and the outcome was a formality after that.
The Spaniard's record at Roland Garros since 2005 is now 62 wins for one loss, that coming against Robin Soderling of Sweden in a 2009 fourth round match.
"It was a positive first week - under control and winning in straight sets is better and I'm happy for that," he said.
The only cloud on the horizon for Nadal was ongoing problems with his troublesome back that caused him to take some of the pace off his serve.
"I felt a little bit my back, that's why I slowed down a little bit the serve," he said.
Next up for the Spaniard, who will turn 28 on Tuesday, is little-known Serb Dusan Lajovic, who saw off American hope Jack Sock 6-4, 7-5, 6-3.
Asked if he would asking for advice on how to tackle Nadal from fellow Serb Novak Djokovic, Lajovic wryly replied: "Yeah, I will try to ask everybody some tips against Rafa.
"You need to have a lot of tips and confidence to beat him, but I hope to enjoy the match if he wins and to give my best."
The man Nadal defeated in last year's final, fellow Spaniard David Ferrer, also reached the last 16 by defeating Andreas Seppi of Italy 6-2, 7-6 (7/2), 6-3.
The fifth seed had little difficulty in despatching a player he had taken on six times previously and not dropped a single set.
He will now go on to take on 19th seed Kevin Anderson of South Africa who moved through when opponent Ivo Karlovic of Croatia retired with a back injury after losing the first set 6-3.
With 35-year-old Karlovic measuring 2.11m (6ft 11in) and Anderson 2.03m (6ft 8in) their towering showdown out on Court 2 had been billed as the tallest match in Grand Slam history, but it lasted only 43 minutes.
Anderson also reached the last 16 last year in Paris, the first South African to do so since Wayne Ferreira in 1996.
At 32, Ferrer was one of 10 men aged 30 or over to reach the third round, the most at any Grand Slam event since 1978 Wimbledon when there were 12.
The highest number of players aged 30 or over through to the round of 16 at Roland Garros was eight in 1969.
American hopes of having three players through to the last 16 for the first time since 1995, when Andre Agassi, Michael Chang and Jim Courier reached that stage, were shattered with the defeat of Sock.
John Isner made the fourth round on Friday and Donald Young could join him there if he defeats Spain's Guillermo Garcia-Lopez.
French interest was high on Saturday with Gael Monfils and Richard Gasquet both hoping to join Jo-Wilfried Tsonga in the fourth round.
Monfils came through another punishing battle with Italian 14th seed Fabio Fognini, winning 5-7, 6-2, 6-4, 0-6, 6-2 after looking to be on the point of abandoning at one point at the end of the fourth set.
"I'm dying. I'm about to collapse," he told the umpire at a changeover, but he promptly moved 3-0 up and, in front of an adoring home crowd, he eventually gained revenge for a 9-7 fifth set loss to Fognini in a 2010 second round match.
Gasquet was on later in the day against tough Spaniard Fernando Verdasco.
Andy Murray was also in action going up against Germany's Philipp Kohlschreiber, who won a tournament on clay in Dusseldorf last weekend.Results on Saturday at the French Open, the seventh day of the
season's second Grand Slam tournament at Roland Garros (x denotes seeded
Rafael Nadal (ESP x1) bt Leonardo Mayer (ARG) 6-2, 7-5, 6-2
Dusan Lajovic (SRB) bt Jack Sock (USA) 6-4, 7-5, 6-3
Kevin Anderson (RSA x19) bt Ivo Karlovic (CRO) 6-3 - retired
David Ferrer (ESP x5) bt Andreas Seppi (ITA x32) 6-2, 7-6 (7/2), 6-3
Guillermo Garca-Lopez (ESP) bt Donald Young (USA) 6-2, 6-4, 2-6, 6-7 (4/7), 6-4
Gael Monfils (FRA x23) bt Fabio Fognini (ITA x14) 5-7, 6-2, 6-4, 0-6, 6-2
Marcel Granollers (ESP) bt Martin Klizan (SVK) 6-7 (5/7), 6-2, 7-6 (7/4), 7-5
Suspended due to darkness
Fernando Verdasco (ESP x24) leads Richard Gasquet (FRA x12) 6-3, 6-2, 2-2
Philipp Kohlschreiber (GER x28) level with Andy Murray (GBR x7) 6-3, 3-6, 3-6, 6-4, 7-7
Svetlana Kuznetsova (RUS x27) bt Petra Kvitova (CZE x5) 6-7 (3/7), 6-1, 9-7
Lucie Safarova (CZE x23) bt Ana Ivanovic (SRB x11) 6-3, 6-3
Sloane Stephens (USA x15) bt Ekaterina Makarova (RUS x22) 6-3, 6-4
Simona Halep (ROM x4) bt Mara Teresa Torr Flor (ESP) 6-3, 6-0
Jelena Jankovic (SRB x6) bt Sorana Cirstea (ROM x26) 6-1, 6-2
Sara Errani (ITA x10) bt Julia Glushko (ISR) 6-0, 6-1
Kiki Bertens (NED) bt Silvia Soler-Espinosa (ESP) 6-2, 6-1
Andrea Petkovic (GER x28) bt Kristina Mladenovic (FRA) 6-4, 4-6, 6-4