Tokyo, July 30 : World No. 1 Novak Djokovic's dream of a Golden Slam came to an end as world No. 4 Alexander Zverev of Germany defeated the Serbian in the semifinals of the men's singles tennis competition at the Tokyo Olympics on Friday. The Serbian had clinched the first set 6-1. But his German opponent made a strong comeback to win the next two sets 6-3, 6-1 in a match which lasted two hours and three minutes under the sweltering heat at the Ariake Tennis Park. It is the first time Zverev has beaten Djokovic since 2018, when the German overcame the Serbian in the final of the ATP Finals tournament in London. With this win, Zverev will now face world No. 12 Karen Khachanov of the Russian Olympic Committee (ROC) in the gold-medal match. "It's incredible beating the best player in the world undoubtedly right now and in this season," Zverev was quoted as saying by olympics.com. "It seemed it was impossible to beat him at this event, so I'm very happy right now. But yet there's still one match to go." Zverev credited a more aggressive approach from himself for making a turnaround in the match. "At some point, I was down a set to break, so I needed to change something," he said. "I started playing much more aggressive, I started to swing through the ball a little bit more, and yeah, I tried to dominate that way." After the end of the match, Djokovic and Zverev hugged each other at the net and exchanged a few words. "I told him that he's the greatest of all time. I know that he was chasing history, is chasing the Golden Slam and was chasing the Olympics, but in these kinds of moments me and Novak are very close," said Zverev. Djokovic had been aiming to become the first man to win all four majors and Olympic gold in the same calendar year. Friday's loss to Zverev means that he can't match the feat Steffi Graf achieved in 1988. He now moves into the bronze-medal match against Pablo Carreno Busta of Spain on Saturday. The 34-year-old has a chance left to go for gold. Djokovic will be partnering alongside Nina Stojanovic in the mixed doubles semifinals against Elena Vesnina and Aslan Karatsev of the ROC later on Friday. Previously, Khachanov moved into the men's singles final at the Olympics with a straight-sets 6-3, 6-3 victory over Carreno Busta. The 25-year-old Russian, who had reached the Wimbledon quarterfinals earlier in the month, outgunned the 11th ranked Spaniard in an hour and 19 minutes. Khachanov broke Carreno Busta's serve twice, striking 12 winners to just four unforced errors in the first set. The 30-year-old Carreno Busta, who had caused an upset by beating world number two Daniil Medvedev in the quarterfinals, had no answer to Medvedev's countryman who came out all guns blazing. Eventually, Khachanov sealed the victory with a forehand winner. /IANS