He aimed to become the first male player to win a “Golden Slam” – consisting of four Grand Slam tournaments and one Olympic gold medal in the same calendar year.
Steffi Graf is the only tennis player to achieve the feat when she did so in 1988.
The Serbian has already won the Australian Open, the French Open and Wimbledon this year. He would have needed the gold medal at the Olympics and the US Open title to complete the package.
Victory in the last grand slam of the year would still take the 34-year-old to 21 major titles, overtaking Roger Federer and Rafael Nadal who each have 20 majors to their name.
After the game, Zverev explained what he and Djokovic said as the pair kissed at the net.
“I told him he was the greatest of all time, and he will be,” Zverev told reporters.
“I know he was chasing the story, chasing the ‘Golden Slam’ and chasing the Olympics, but in times like these, me and Novak are very close.
“Of course I’m happy I won, but at the end of the day I know how Novak feels.”
Djokovic hadn’t lost a single set at the Games before Friday’s game and looked menacing as he pushed his opponents aside.
And the same story seemed to be playing out against Zverev, as the US Open 2020 finalist failed to keep up with Djokovic’s intensity from the start.
However, after the interlude between the first two sets, he appeared to pull himself together and strike back, showing courage and determination.
His big, powerful serve and devastating forehand put him on the front foot, while Djokovic showed signs of nervousness as unusual unforced errors crept into his performance.
A bathroom break between the second and third set seemed to stop Zverev’s momentum, but it wasn’t for long.
In the shortened three-set format for the men’s competition at the Olympics, Djokovic was unable to return as Zverev stayed on track for his first Olympic gold, winning the final two sets within an hour and 26 minutes.
Zverev, 24, will now meet Karen Khachanov of the Russian Olympic Committee in the gold medal match this weekend.
“It’s an amazing feeling to know that you are going to bring the medal home to you in Germany,” said Zverev. “It’s amazing to beat the best player in the world without a doubt right now and this season.
“It seemed like it was impossible to beat him in this event so I’m very happy right now. But there is still one game to play.”
Meanwhile, Djokovic and Spaniard Pablo Carreño Busta will face off for the bronze medal.
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