Zverev and Thiem win to set up French Open quarterfinal

Second-seeded Alexander Zverev has reached his first Grand Slam quarterfinal the hard way, beating Karen Khachanov 4-6, 7-6 (4), 2,6, 6-3, 6-3 on Sunday for his third straight comeback win in five sets.

The latest gritty victory came with the usual temper flare-ups from Zverev. But the German player also showed, once again, that he knows how to dig deep when it matters. In all three of his five-setters at Roland Garros he has trailed 2-1 in sets.

Zverev says he spends up to four hours each day working on weights and fitness.

He might well need to up that schedule considering his quarterfinal opponent is No. 7 Dominic Thiem of Austria, who is one of the fittest players on the men's circuit and has reached the past two semifinals at Roland Garros.

Almost 12 hours altogether so far.

Thiem, who has played three straight four-setters, beat No. 19 Kei Nishikori of Japan 6-2, 6-0, 57, 6-4 on Court Philippe Chatrier.

Nishikori won just 14 points in the first set and nine in the second, losing to Thiem for the first time.

The 24-year-old Thiem leads 4-2 overall against Zverev, but lost to him last month in the Madrid Masters final. Thiem called their upcoming quarterfinal "the matchup most of the fans in Germany and Austria were hoping for when they saw the (French Open) draw."

On Court Suzanne Lenglen, Zverev's smash at the net gave him match point, which he took when Khachanov netted a forehand. Zverev sank to his knees in celebration. He then patted Khachanov, a friend from their junior days, sympathetically on the chest before pumping his arms in celebration.

As in the previous two rounds, Zverev was struggling for consistency. This was illustrated in the 10th game of the second set.

Zverev was serving for the set at 5-4, he soon trailed 0-40.

Then, in a blur Zverev won the next four points to give himself a set point — only to miss a smash from near the back of the court. An ace gave him another set point but he missed that one, too, putting a low volley into the net.

On his third set point, the erratic Zverev found the net again with a sloppy backhand. Khachanov punished him and broke for 5-5.

The second-set tiebreaker was scrappy, Zverev clinching it with an ace to level the match.

Zverev has youth on his side, but he has been spending long on court and his body is showing it.

At the start of the fifth set, he had a medical time out for treatment for an apparent blister on his left foot.

It did not seem to impede him, however.

He broke immediately for a 1-0 lead and jumped around on court, waving his arms to get the crowd going.

Later Sunday, Novak Djokovic was facing Fernando Verdasco on Court Philippe Chatrier, where he won the last of his 12 majors in 2016.

In women's play, 13th-seeded Madison Keys reached the quarterfinals for the first time at Roland Garros after beating No. 31 Mihaela Buzarnescu of Romania 6-1, 6-4 on Chatrier.

Keys next faces unseeded Yulia Putintseva of Kazakhstan, who beat 26th-seeded Czech Barbora Strycova 6-4, 6-3.

If she wins that match, Keys could meet Stephens in the semifinals.