LONDON, Nov. 20 (Xinhua) -- World number one Novak Djokovic defeated 2018 champion Alexander Zverev 6-3 and 7-6 (7-4) to qualify for the semifinals at the ATP Finals for the ninth time here on Friday.
The Serb, losing his second group match to Russian fourth seed Daniil Medvedev two days ago, had to beat Zverev to reach the last four.
He made a strong start in the first set and kept his composure to finish his job in the tiebreak in the second set.
"I managed to serve well in the important moments and contrary to the last match against Daniil, I just managed to find the right shots at the right time," said Djokovic, who will fight for a final place against Austrian third seed Dominic Thiem.
"He's in a very good form. He loves to play in this surface," Djokovic commented on his next opponent. "He's a Grand Slam champion. Obviously, that's a huge boost for him. Got that kind of pressure and expectation off his back. So I'm sure that allows him to kind of also swing freely on the court and play even better than he did before."
In the evening session, Medvedev breezily past Argentine debutant Diego Schwartzman 6-3, 6-3, winning all three group matches in straight sets.
The 24-year-old Russian will face Rafael Nadal on Saturday, as the 20-time grand slam champion is still await for a trophy of the year-ending tournament.