Novak Djokovic recovered from his first dropped set at this year's French Open to reach the quarter-finals, while Rafa Nadal had things much easier in claiming his last-eight spot.

The world number on was playing his first match since learning of the death of his childhood coach and mentor, Jelena Gencic, two days ago.

He was sluggish early on, but came back to beat Philipp Kohlschreiber 4-6 6-3 6-4 6-4.

Rafael Nadal found his form on his 27th birthday to brush aside 13th seed Kei Nishikori of Japan 6-4 6-1 6-3 to seal his place in the quarters. 

And local favourite Richard Gasquet was the gallant loser yet again as he bowed out 6-7(5) 4-6 6-4 7-5 8-6 to Swiss ninth seed Stanislas Wawrinka.

German 16th seed Kohlschreiber has a fine one-handed backhand - half the quarter-finalists in the men's singles use the single hander - and he broke Djokovi's serve in the fifth game.

Kohlschreiber needed a lucky break to take the set, saving two break points himself before clinching it when his backhand hit the top of the net and dropped dead.

Djokovic's only loss to Kohlschreiber came at Roland Garros four years ago. The Serb is a much better player now, of course, but he had the same listless air as when he found himself two sets down against Andreas Seppi at the same stage last year.

He fought back then and he did so again today, gradually upping his level, although Kohlschreiber will look back on only two of 13 break points taken and see a missed opportunity.

It was particularly the case in the second set, when Djokovic was still well below par, and when Kohlschreiber did finally break for a second time it was when his opponent was serving for the match.

Djokovic made no mistake the second time, clinching victory in two hours and 42 minutes to set up a date with 12th seed Tommy Haas.

The first set in Nadal's match was relatively even, but the Spaniard took his chance in the fifth game while Nishikori was not able to take his.

After the Japanese player held at the start of the second set, Nadal won seven straight games, and a single break in the fourth game of the third set was enough for the third seed to come through in two hours and two minutes.

After the match, Nadal was presented with a huge layered cake decorated with tennis rackets and balls on the court as he celebrated his birthday at Roland Garros for the eighth time.