Novak Djokovic overcame a slow start Monday at the French Open to reach his 16th consecutive Grand Slam quarterfinal by beating Philipp Kohlschreiber 4-6, 6-3, 6-4, 6-4.

After losing a set for the first time in the tournament, Djokovic became more aggressive, punctuating winners with lots of fist-pumping as he pulled away.

He repeatedly escaped trouble with his serve, erasing 11 of the 13 break points he faced.

Djokovic will next play 35-year-old Tommy Haas, who became the oldest French Open men's quarterfinalist since 1971 by beating Mikhail Youzhny 6-1, 6-1, 6-3. Haas is also the oldest man to reach the quarters at any major event since Andre Agassi at the 2005 U.S. Open.

Victoria Azarenka swept the final nine games and advanced to the women's quarterfinals by beating 2010 champion Francesca Schiavone 6-3, 6-0. Azarenka will next play Maria Kirilenko, who reached her first French Open quarterfinal by ending the surprising run of 67th-ranked American Bethanie Mattek-Sands, 7-5, 6-4.

Roland Garros is the only major tournament Djokovic has yet to win, and with three more victories he would become the eighth man to complete a career Grand Slam. The six-time major champion has said the French Open is his most important tournament this year.

Even so, Djokovic was subdued at the start of the match, his first since he learned that his first coach, Jelena Gencic, had died in Belgrade, at age 76. She mentored him for about five years, starting when Djokovic was 6.

With the victory, Djokovic avenged a straight-sets loss to Kohlschreiber in the third round at Roland Garros in 2009. The No. 1-ranked Djokovic seeks to become the first man since Jim Courier in 1992 to win the Australian Open and French Open in the same year.

Djokovic's streak of consecutive major quarterfinals is the third longest among men in the Open era.

Haas became a first-time Roland Garros quarterfinalist in his 12th appearance at the tournament, a record for such a breakthrough. He's the first German man to reach the final eight since Michael Stich and Bernd Karbacher in 1996.

And he's the oldest men's quarterfinalist at Roland Garros since 39-year-old Istvan Gulyas in 1971.

"These are cool stats sometimes to hear," said Haas, who is mounting a comeback from injuries that sidelined him for more than a year. "I feel like I'm riding a wave that I hope to continue as long as I can. I'm going out there and I try to improve my game as much as I can, and to be in this situation is spectacular."

Seeded No. 12, Haas needed 13 match points to beat John Isner in a third-round marathon, but his victory over Youzhny took less than 90 minutes. By the second set Youzhny was so frustrated he demolished his racket by banging it nine times against his changeover chair.

"Bad luck for that racket," Youzhny said.

Haas served well and dominated with his returns, winning 25 of 41 points on Youzhny's first serve and breaking eight times.

Ranked No. 2 when he was 24, Haas is now the oldest player in the top 100. He was sidelined from February 2010 to April 2011 because of hip and shoulder injuries, but he's 25-9 this year, and his ranking his risen to 14th from 205th at the beginning of 2012.

"Who would have thought two years ago I'd be in this position today?" Haas said. "I wouldn't have thought that way. Almost no way. But you've got to keep believing and have the right people around you being positive, helping you to maybe still achieve great things."

The women began play in weather so cool that both dressed in long sleeves, and Azarenka wore leggings under her skirt. From the baseline the two traded strokes and grunts.

"Ah-heee!" Azarenka shrieked.

"Wah-hooo!" Schiavone responded.

There were four consecutive service breaks before Azarenka took the lead for good, holding to make it 4-3. The superior pace and depth of her shots began to wear on the unseeded Schiavone, and Azarenka took charge by winning 11 of 12 points during a stretch late in the first set.

The Belarusian broke serve seven times and committed only 14 unforced errors.

"It was definitely a very good challenge for me to play against Francesca, especially knowing how well she's done here in the past," Azarenka said. "I'm glad with the way I played today."

Seeded No. 3, Azarenka improved to 26-2 in 2013. She has won the Australian Open each of the past two years, and Roland Garros is the only major tournament where she has yet to reach the semifinals.

"The next step is quarterfinals," Azarenka said. "Never been past it here, so it would definitely be a much better result."

No. 12 Kirilenko overcame a 4-1 deficit against Mattek-Sands, who stunned 2011 French Open champion Li Na in the second round. Leading 5-4, Mattek-Sands asked for medical attention, and from there, Kirilenko won four games in a row.

Kirilenko, who is engaged to two-time NHL MVP Alex Ovechkin of the Washington Capitals, also was visited by a trainer, getting a massage on her right shoulder in the second set.