PHOTOS: Birthday boy Nadal reaches last eight in style

Rafael Nadal earned his second straight sets victory in succession as his challenge for an eighth French Open title gathered pace with a 6-4, 6-1, 6-2 defeat of Japan's Kei Nishikori to secure a quarter-final spot on Monday.

Troubled in his first two rounds where he had to come from a set back, Nadal celebrated his 27th birthday in style with a brutal demolition of 13th seed Nishikori.

Only in the first set did Nishikori, looking to become only the second Japanese man to reach the last eight in Paris, offer any sort of challenge to the defending champion.

Nadal broke serve with the aid of a fortunate net cord in the fifth game of the opener and that proved enough for him to take the first set.

Nishikori had a glimmer of a chance when he had a break point in the second game of set two but failed to convert it and was broken in the next game when he flailed a high backhand volley into the tramlines.

From then on Nadal was in total command and finished the match by hooking a forehand winner down the line after a little over two hours before waving to the crowd as they sang happy bithday to the the king of clay.

"To celebrate my birthday here on centre court in Paris is a very special moment for me," Nadal said courtside before a huge birthday cake was wheeled on to court.

World number one Novak Djokovic overcame the loss of his first set of the tournament to advance to the French Open quarter-finals with a 4-6, 6-3, 6-4, 6-4 victory over 16th seed Philipp Kohlschreiber on Monday.

The top-seeded Serb opened up sluggishly as German Kohlschreiber fired on all cylinders.

Djokovic quickly regained control though, breaking early in each set and saving a few break points on the way to a somewhat uneventful victory.

He next faces German Tommy Haas, the 12th seed, for a place in the semi-finals as he bids to land the trophy at Roland Garros for the first time.

Australian Open champion Azarenka's clash with 2010 Roland Garros winner Francesca Schiavone had been billed as the pick of the women's fourth round showdowns but it failed to draw in the crowds.

The discerning Parisian fans chose to turn a deaf year to the ear-splitting sounds that emitted out of Philippe Chatrier Court first thing in the morning as third seed Azarenka completed a 6-3, 6-0 win over the Italian in front of a quarter full arena.

Over the years the Belarussian's sound effects have been compared to those made by jet liners or even women giving birth but with Schiavone also chipping in with her kung-fu style yelps, it was definitely not a contest for the purists.

It was only when a victorious Azarenka twirled around to blow kisses to the four corners of the court that fans started arriving.

Tommy Haas became the oldest man to reach a grand slam quarter-final since 2005 with a 6-1, 6-1, 6-3 thrashing of Russia Mikhail Youzhny at the French Open on Monday.

The 35-year-old former world number two, enjoying an Indian summer to his injury-hit career, left Youzhny smashing rackets in frustration as he cruised to victory in 84 minutes.

Andre Agassi was the last 35-year-old to reach a grand slam quarter-final at the 2005 U.S. Open.

With Djokovic, Haas, Youzhny and Azarenka grabbing all the limelight, barely anyone noticed 12th seed Russian Maria Kirilenko setting up a last-eight meeting with Azarenka following a 7-5, 6-4 win over American Bethanie Mattek Sands.