Still grieving, Djokovic began shakily Monday. Six of the match's first seven unforced errors were his. After one poor exchange, he chucked his racket hard enough to break it. He dropped a set for the only time in four matches so far.
After recovering quickly to dispatch 16th-seeded Philipp Kohlschreiber of Germany 4-6, 6-3, 6-4, 6-4 and reach the quarterfinals at a 16th consecutive major tournament, Djokovic spoke from the heart about the passing of Jelena Gencic, who was 76.
"It hasn't been easy, but this is life. You know, life gives you things (but also) takes away close people," Djokovic said. "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."
Gencic connected with a 6-year-old Novak at a tennis camp, then worked with him for five years.
"I feel even more responsible now to go all the way in this tournament," said the No. 1-ranked Djokovic, who owns six Grand Slam titles but none from Roland Garros. "I want to do it for her."
He'll need to beat three more opponents to accomplish that, starting with 12th-seeded Tommy Haas, who at 35 became the oldest French Open quarterfinalist since 1971 by eliminating Mikhail Youzhny 6-1, 6-1, 6-3 in less than 1 1/2 hours.
By the second set, Youzhny was so out of sorts he destroyed a racket by slamming it nine times against his sideline seat.
Haas is a four-time Grand Slam semifinalist who climbed to No. 2 in the rankings at age 24. But recent times have been difficult because of a series of serious injuries and operations, including to his right shoulder and hip, and he missed more than a full season.
"Who would have thought two years ago I'd be in this position today?" Haas asked. "I wouldn't have."
He's certainly persistent.
The 12 French Open appearances it took Haas to reach his first quarterfinal in Paris is a record. And he needed 13 match points in the third round to get past John Isner in five sets.
"It's easy sometimes to ... throw the white towel and say, 'I'm done. I have achieved a lot of things. I don't really have to worry so much financially and I can live a good life.' But at the same time," Haas explained, "maybe there was something in me still that said, 'You know what? I can maybe still do something.'"
If Djokovic can get past Haas, he'll find a familiar foe in the semifinals: Seven-time French Open champion Rafael Nadal, who played his first relatively routine opening set of the tournament and put together a 6-4, 6-1, 6-3 victory over No. 13 Kei Nishikori of Japan.
Nadal, who beat Djokovic in last year's final and is 56-1 in his French Open career, declared: "I played much better today than the first three matches. No doubt about that."
Consider that something of a warning for No. 9 Stanislas Wawrinka, who was trailing by two sets when he got into an extended and animated argument with the chair umpire, demanding that a line judge be replaced. Wawrinka slowly, steadily turned the match around and won 6-7 (5), 4-6, 6-4, 7-5, 8-6.
Gasquet tired as the match stretched past four hours and, asked afterward where he felt pain, replied: "In the soul, for sure. A little bit in the leg, too. But more in the soul."
Nadal began the first round by losing the first set. Did the same in the second round. In the third, he was taken to an opening tiebreaker. On Monday, Nishikori started well, winning each of the first five points that lasted at least 10 strokes, no easy feat against Nadal.
Ahead 2-1, Nishikori earned two break points with a forehand winner that had Nadal rolling his eyes. That, though, is when Nadal really got going. A short return set up a backhand winner to erase one break point, and a 121 mph (195 kph) ace took of the other. Nadal broke in the next game, helped by Nishikori's three unforced errors.
"One bad game for me," Nishikori said, "and he (started) playing well."
Nadal was in control the rest of the way on the day he turned 27. The crowd helped him celebrate by singing "Happy Birthday" in French as he was presented with an enormous layered cake festooned with rackets and yellow tennis balls.
"That," said the tournament's other defending champion, Maria Sharapova, "was a pretty cool cake."
She moved into the quarterfinals by beating 17th-seeded Sloane Stephens of the United States 6-4, 6-3, part of a rough day for Americans. The other two in action also exited in straight sets: 54th-ranked Jamie Hampton lost to 18th-seeded Jelena Jankovic 6-0, 6-2, and 67th-ranked Bethanie Mattek-Sands was beaten by 12th-seeded Maria Kirilenko 7-5, 6-4. Kirilenko, who's engaged to two-time NHL MVP Alex Ovechkin of the Washington Capitals, now meets two-time Australian Open champion Victoria Azarenka, a 6-3, 6-0 winner over 2010 French Open titlist Francesca Schiavone.
Fifteen-time major champion Serena Williams, the only U.S. singles player left, plays her quarterfinal against 2009 French Open champion Svetlana Kuznetsova on Tuesday, when No. 4 Agnieszka Radwanska faces No. 5 Sara Errani. The men's quarterfinals Tuesday are 17-time major champion Roger Federer against No. 6 Jo-Wilfried Tsonga, and No. 4 David Ferrer against No. 32 Tommy Robredo, the first man in 86 years to win three consecutive Grand Slam matches after dropping the opening two sets.
For Federer, this is the 36th Grand Slam quarterfinal in a row, a record for the 45-year Open era. Djokovic's streak isn't even half as long, but it ranks third.
The last time the Serb failed to get that far at a major tournament was the 2009 French Open, where he lost to Kohlschreiber in the third round. Once out of Monday's tricky first set, Djokovic found his strokes and, most of all, his serve, which erased 11 of 13 break points.
His former coach, Gencic, died Saturday, when Djokovic played his third-round match, but his entourage kept the sad news secret from him until after that victory. In April 2012, during a tournament at Monte Carlo, Djokovic found out hours before playing a match that his grandfather died.
That experience, Djokovic said, "helped me a little bit to kind of stay tough this time, because it took me a long time last year to recover. It was very emotional. This year, of course, again, very close person, so another shock for me. But I'm handling it better. I'm trying to focus my thoughts on the nicest memories."
Djokovic last spent time with Gencic when he visited Belgrade a couple of months ago. Their final phone conversation, he said, was two weeks ago, shortly before the French Open.
"She was honest and open," Djokovic recounted. "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."
Follow Howard Fendrich on Twitter at http://twitter.com/HowardFendrich