PARIS — Five rounds into the French Open, king of clay Rafael Nadal still awaits a serious challenge.

Novak Djokovic hopes to provide it in the semifinals.

Three-time defending champion Nadal matched the most lopsided Grand Slam victory of his career Tuesday, defeating fellow Spaniard Nicolas Almagro 6-1, 6-1, 6-1. The drubbing equaled the standard Nadal set in his previous victory, when he lost three games against another Spaniard, Fernando Verdasco.

Nadal was giving the center-court crowd a thumbs-up signal following his triumph shortly after Djokovic completed a much more arduous win on Court Suzanne Lenglen. He needed more than three hours to eliminate childhood friend Ernests Gulbis 7-5, 7-6 (3), 7-5.

The No. 3-seeded Djokovic will play No. 2 Nadal in an anticipated showdown Friday, with No. 1 Roger Federer looming as a potential opponent for the winner in the final.

Nadal is 26-0 at Roland Garros, but Djokovic is making a mark in the record book, too. The Australian Open champion has reached five consecutive Grand Slam semifinals, joining Federer, Ivan Lendl and Boris Becker as the only men to accomplish the feat in the 40-year Open era.

With less fanfare, No. 2-seeded Ana Ivanovic and No. 3 Jelena Jankovic advanced to the women's semifinals Thursday. Ivanovic beat Patty Schnyder 6-3, 6-2, and Jankovic defeated unseeded Carla Suarez Navarro 6-3, 6-2.

Nadal celebrated his 22nd birthday with nearly flawless tennis, committing only nine unforced errors. He lost the first game, then won nine in a row — his longest such streak since his previous match, when he swept 10 in a row.

The rout was especially impressive because the No. 19-seeded Almagro is no slouch on clay, with a tour-high 29 victories on the surface this season.

It was only the third time a man has lost fewer than four games in a Grand Slam quarterfinal in the Open era. It was a record for that era at the French Open.

Djokovic's match was much more competitive, largely because he failed to convert his first 11 break-point chances. He came through on the 12th to end the first set, thanks to an unforced error by Gulbis, then raised his arms in mock triumph.

Djokovic continued to struggle in the second set, falling behind 3-1, and then began to strike the ball more crisply and consistently. In the tiebreaker he took the lead for good by hitting an ace and winning a 19-shot rally on the first two points, and in the third set he won eight of the final nine points to close out the victory.

The 19-year-old Gulbis showed his first Grand Slam quarterfinal berth was no fluke, displaying a mix of power and finesse that kept Djokovic off balance. The two practiced together as youngsters at a German tennis academy. When their match was over, Djokovic gave Gulbis a pat on the chest as both smiled.

The No. 2-seeded Ivanovic struggled against the 10th-seeded Schnyder only when trying to close out the victory. With light rain beginning to fall, she hit her second and third double-faults of the match in the final game before smacking a service winner on the third match point.

"I started to rush," Ivanovic said. "I was happy to calm down and still win the game."

Ivanovic has reached the semifinals at four of the past five Grand Slam tournaments, starting with her run at the French Open a year ago, when she lost to Justine Henin in the final.

"I am really happy the way I'm playing," said Ivanovic, who has yet to lose a set in five matches. "I just want to keep this level."

Svetlana Kuznetsova advanced to the quarterfinals for the third year in a row by completing a victory over Victoria Azarenka, 6-2, 6-3. Kuznetsova's opponent Wednesday will be Kaia Kanepi, who became the first Estonian to reach the quarterfinals at a major tournament by beating Petra Kvitova 6-3, 3-6, 6-1.

Kanepi and Kuznetsova won matches suspended Monday because of darkness.

In an all-Russian quarterfinal Wednesday, No. 7-seeded Elena Dementieva will play No. 13 Dinara Safina. Federer will face No. 24 Fernando Gonzalez in the men's quarterfinals, and No. 5 David Ferrer will meet unseeded Gael Monfils, the only French player remaining.