Rafael Nadal tightened a Spanish stranglehold on the bottom half of the French Open draw on Saturday, while Andy Murray set up a last 16 round clash with Richard Gasquet.

The top seed and defending champion coasted into the fourth round with a lop-sided 6-1, 6-3, 6-4 win over qualifier Eduardo Schwank of Argentina.

Earlier sixth-seeded David Ferrer flattened Russia's Mikhail Youzhny 6-0, 6-2, 6-2 in just 101 minutes, whilst 12th seed Nicolas Almagro saw off the challenge of Argentina's Leonardo Mayer 6-4, 6-1, 6-2.

Marcel Granollers then edged a hard-fought 6-4, 6-4, 1-6, 4-6, 6-1 win over French wildcard Paul-Henri Mathieu to ensure that half of the qualifiers for the last 16 in the bottom half of the draw were from Spain.

In contrast, there were no Spaniards through in the top half of the draw.

Murray looked to be over the lower back problems that beset him in the previous round as he defeated Santiago Giraldo of Colombia 6-3, 6-4, 6-4.

Nadal ready to confront Monaco

Nadal, who turns 26 on Sunday, had Schwank on the defensive from the start, jumping out into a 4-0 lead that set the tone for the entire match.

In the end he conceded just eight games, taking his total in three matches to a meagre 17.

The Spaniard is set on winning the French Open for a record seventh time in eight years, having first played at Roland Garros in 2005 as an 18-year-old.

With a match record of 48-1 in his favour Nadal next goes up against Juan Monaco of Argentina who defeated Milos Raonic of Canada 6-7 (5/7), 6-3, 6-7 (5/7), 6-3, 6-4.

"I have started well the tournament - into the second week now, that is the most important thing," he said.

"Now I have a big confrontation against Monaco. He is having a fantastic season."

Ferrer dominated

The 30-year-old Ferrer, who has yet to make it past the quarter-finals at Roland Garros despite being one of the best players on clay for the last few years, had Youzhny by the throat from the start, winning the first set 6-0 and leading 2-0 in the second before the Russian got off the mark.

Thereafter Ferrer conceded just another three games as he set up a last 16 round meeting with Granollers.

"This match was easier than planned, and I was immediately into the match," he said.

"When the situation was a bit difficult, I managed to overcome these difficulties.

Almagro's routine win over Mayer was his seventh straight victory following his title triumph in Nice last week.

His previous best at Roland Garros were quarter-final appearances in 2008 and 2010 and on both occasions he lost to Nadal who he will face again should the two Spaniards make it through to the last eight.

Murray faces criticism

On his rest day Friday, Murray had been left fielding criticism from such as British legend Virginia Wade and French champion Henri Leconte that he had acted in an unsportsman-like manner in his win over Jarkko Nieminen on Thursday.

In that tie he had looked down and out in the first few games, clutching at his lower back and legs and needing medical treatment three times.

After dropping the first set 6-1, Murray suddenly settled down in the second and eventually ran out an easy winner.

Many felt his actions could have destabilized his opponent whose game fell apart after the opening set.

Against Giraldo though there was no sign of the back spasms that Murray said had been the problem against Nieminen and a single break in each set was enough to put him through into the last 16 at Roland Garros for the fourth straight year.

"Obviously it was very hot today and I warmed up very quickly," he said.

"I felt better yesterday when I woke up than I had the day before, and then had a very light practice.

"I woke up this morning again feeling better than I did, but that's because of the work my physio has done the last 48 hours and all the recovery work that we've done between the last match and now."

Also through to the last 16 was eighth seed Janko Tipsarevic of Serbia who worked his way past Frenchman Julien Benneteau 6-3, 7-5, 6-4.

Tipsarevic won the last five games of the match after being 4-1 down in the third set to reach the last 16 at Roland Garros for the first time and will next take on Almagro.

There was better news for home fans with the victory of 17th seed Richard Gasquet 6-7 (3/7), 6-3, 6-0, 6-0 over German veteran Tommy Haas.

Gasquet, who won 13 games in a row from 5-3 ahead in the second set to destroy Haas, will next play Murray in a bid to reach the French Open last eight for the first time.