Alexander Zverev missed the final at the Masters 1000 tournament in Paris and missed the chance for his sixth title this year.
The 24-year-old Olympic champion from Hamburg had to admit defeat to the Russian US Open winner Daniil Medvedev in 80 minutes with 2: 6, 2: 6 on Saturday.
This means that the US Open final between Medvedev and world number one Novak Djokovic will be relaunched in the final on Sunday.
Medvedev defeated the 34-year-old Serb in New York.
Due to the defeat in the final, Djokovic missed the Grand Slam - winning the four most important tournaments in a calendar year.
Previously, he had won the Australian Open, the French Open and Wimbledon, but also failed to achieve the desired Olympic victory due to the semi-final defeat against Zverev.
Zverev had won the tournament in Vienna a week ago, but had no chance against the strong ranking second Medvedev.
By moving into the final, it is already certain that Djokovic will be number one in the world rankings for the seventh time at the end of a season and will thus set a record.
Djokovic won his semi-finals 3: 6, 6: 0, 7: 6 (7: 5) against the Pole Hubert Hurkacz.
He shared the record so far with the American Pete Sampras, who had finished the season as number one for six consecutive years from 1993 to 1998.
Djokovic was already in first place in 2011, 2012, 2014, 2015, 2018 and 2020 at the end of the year.
The Spaniard Rafael Nadal (2008, 2010, 2013, 2017, 2019) and the Swiss Roger Federer (2004 to 2007, 2009) each achieved this five times.