Thiem and Zverev are best friends on and off the tour. it will be an emotional rollercoaster for them both but Thiem will probably win this match and claim his first Grand Slam. To be fair Thiem certainly deserves it because he has been knocking on the door a long time now.
Here is Thiem recent Grand Slam record and the reason why I think he will win the US Open:
2016: French Open semi-final (lost to Djokovic)
2017: French Open semi-final (lost to Nadal)
2018: French Open finalist (lost to Nadal)
2019: French Open finalist (lost to Nadal)
2020: Australian Open finalist (lost to Djokovic)
2020: US Open finalist
Thiem has already beaten Djokovic and Nadal at Grand Slams and is finally at the age of 27 on his way to becoming a multiple Grand Slam winner. His record at the French Open shows he will be second favourite behind Nadal to win it and he already made the Australian Open final in 2020.
@JollyGood Zverev vs Thiem is the dream finale for this tournament, and I believe that this match will be really long, because both will badly want to win this tournament, and they won’t give up till the very end. Also I agree with your prediction as I too believe that Thiem has an excellent chance of winning this tournament, but then again we should not underestimate Zverev too because he definitely has the potential to defeat Thiem.