Each of the top four men's seeds have reached the 2019 French Open semi-finals after Novak Djokovic and Dominic Thiem won their respective matches on Thursday to book their spots in Friday's draw.

Top pick Djokovic beat fifth seed Alexander Zverev 7-5, 6-2, 6-2 after a wobble at the end of their first set and will feature in the last four at Roland-Garros for the first time since he last won the contest in 2016.

Thiem had even less trouble in his quarter-final and took under two hours to defeat Karen Khachanov 6-2, 6-4, 6-2, with the Austrian booking his fourth successive appearance in a French Open semi.

Unseeded Amanda Anisimova knocked defending champion Simona Halep out of the women's singles in a 6-2, 6-4 win of mighty proportions, and she'll face eighth seed Ashleigh Barty in Friday's draw.

Barty had her defences up against Madison Keys and held the American 6-3, 7-5 to continue what's been by far her best run in this tournament.

Men's Quarter-Final Results

(1) Novak Djokovic bt. (5) Alexander Zverev: 7-5, 6-2, 6-2

(4) Dominic Thiem bt. (10) Karen Khachanov: 6-2, 6-4, 6-2

Women's Quarter-Final Results

Amanda Anisimova bt. (3) Simona Halep: 6-2, 6-4

(8) Ashleigh Barty bt. (14) Madison Keys: 6-3, 7-5

Semi-Final Draw, Friday's June 7

Men's Singles, Court Philippe Chatrier

(2) Rafael Nadal vs. (3) Roger Federer, 11:50 a.m. BST/6:50 a.m. ET

(1) Novak Djokovic vs. (4) Dominic Thiem

Women's Singles (Court)

(26) Johanna Konta vs. Marketa Vondrousova, 10 a.m. BST/5 a.m. ET (Simonne Mathieu)

(8) Ashleigh Barty vs. Amanda Anisimova, 10 a.m. BST/5 a.m. ET (Suzanne-Lenglen)

Recap

A rougher-than-usual start on Thursday almost saw Djokovic drop a set for the first time this tournament against Zverev, who looked promising early on before wilting in the second and third acts.

Djokovic even surrendered a point to Zverev during the first after the German flagged an umpire's decision. The Serb inspected the line himself and chose to overrule the call.

Zverev couldn't capitalise despite taking a crucial break to lead 5-4. As far as responses go, Djokovic's was as good as they come, conceding just six points across the next three games to clinch back-to-back breaks and edge the set 7-5.

The Serb averaged an 80 percent win rate on his first serve across the match and proved equal to Zverev's best even when the tides looked to have turned, via Tennis TV:

The break statistics were telling as Zverev squandered seven of his eight chances, while his opponent won six of the 11 break points he encountered.

Thiem held an even more dominant record against Khachanov, who failed to get even one break opportunity in three one-sided sets.

The 25-year-old has shown he has a taste for the Paris clay in recent years, and he lines up as part of an elite semi-final bracket, per the ATP:

The surprises haven't stopped coming in the women's draw, and 17-year-old Anisimova continued to bear her teeth at the opposition by knocking out Roland-Garros titleholder Halep.

Third seed Halep won't retain her crown, while her teenage opponent broke a 22-year-old record and could be eyeing a fantastic opportunity at a maiden major of her own, per WTA Insider:

Anisimova beat the Romanian despite recording seven more unforced errors, and Halep looked beaten against the American's defence as she recorded just 16 winners in a straight-sets loss.

Barty is only 23 herself and will be wary of a fellow young contender, having knocked Keys out of the running to mark her fourth victory over an American opponent in Paris this year.

The Australian is now one of the four left in contention to win the women's title, and each is seeking a first Grand Slam trophy. It would have been a first for Keys, too, and she was disappointed to lose a close matchup despite recording three winners more than Barty (19-16).

Tennis writer Jose Morgado noted a welcome boost to Barty's WTA status:

Barty will hope Anisimova is the fifth American she beats in the tournament this year, but a relentless display against Halep has the younger of the pair looking unstoppable at present.  

All statistics provided by Roland-Garros