PARIS -- For the better part of an hour, Germany's Philipp Kohlschreiber created the fleeting impression he might deliver Rafael Nadal an exquisite 27th birthday gift: a victory over No. 1 seed Novak Djokovic.
But after losing the first set, the steely Serb rallied to win 4-6, 6-3, 6-4, 6-4. Nadal, the No. 3 seed, booked his own berth in the quarterfinals 2½ hours later with a 6-4, 6-1, 6-3 victory over Kei Nishikori.
Even with one round to play -- seemingly a formality, with Djokovic meeting Tommy Haas and Nadal taking on Stanislas Wawrinka -- it looks as if the French Open will get its widely anticipated semifinal: Djokovic versus Nadal.
Clearly, Djokovic was not engaged early on against Kohlschreiber, probably a result of the death Saturday of his first tennis coach, Jelena Gencic. This was the first match for Djokovic since learning the news in the locker room after his third-round match.
"It hasn't been easy, but this is life," he said. "Life gives you things, takes away close people in your life, and Jelena was my first coach, like my second mother. We were very close throughout my whole life, and she taught me a lot of things that are part of me, part of my character today, and I have nicest memories of her.
"She never got married, she never had kids, so tennis was all she had in life. She's one of the most incredible people I ever knew. So it's quite emotional, yeah."
Kohlschreiber, playing with extraordinary bounce, broke Djokovic in the fifth game of the opening set and clinched the frame when his backhand clipped the net chord and landed safely. The German held up his hand in classic "sorry" fashion and exhaled comically as he walked to the changeover chair.
Soon, it got a lot harder to breathe.
Kohlschreiber, who upset Djokovic here in straight sets in the 2009 third round, was broken in the fourth game of the third set and never recovered. Djokovic, with four more unforced errors than winners, closed out the No. 16 seed in 2 hours, 42 minutes.
Nadal, meanwhile, came into the fourth round with some scratchy play that made headlines around the world. The Wall Street Journal pointed out that his winning percentages for games and points were well below his usual standards through three rounds. And his unforced errors were up.
The tournament favorite lost the opening sets of his first two matches, a first, and could have lost the third, too. Against Nishikori, Nadal had an indifferent start but gradually accelerated. He's 5-0 against the No. 13 seed, who managed to beat Roger Federer last month in Madrid.
It was Nadal's best performance here to date and should dispel the notion that he somehow isn't quite right. He couldn't stop smiling after the match when the French Tennis Federation presented him with an outsized four-layer cake on Chatrier. There was also a bouquet of flowers, presented by ball girls, and a bag of gear from the Roland Garros store.
"I played much better today than the first three matches, no doubt about that," Nadal said later. "I started to have feelings with my forehand, I started to change directions well. I started to feel that I can hit the ball longer and having more confidence in every stroke. First few days when I was hitting my forehand, my feeling was I don't know if the ball is going to go inside or outside.
"Seriously, if you told me two days ago, 'You will play like this today,' I will say, 'Give me the paper and I will sign,' because I'm happy the way I improved my game today."
Nadal is intent on winning his eighth title in nine years at Roland Garros. But Djokovic revealed Monday he has some added motivation to win his first French Open championship.
About two weeks ago, Djokovic had his last conversation with Gencic.
"She never held any words, to me or to anybody close," Djokovic said of that phone call. "That's why people respected her, because she was honest and open. She told me, 'Listen, you have to focus, you have to give your attention to this tournament. This is a tournament you need to win.'
"She was giving me this kind of inspiration and motivation even more. So now I feel in her honor that I need to go all the way. But, again, it's not about me only. There are so many great players around still in the tournament. It gives me that inner strength, you know, to push even harder."