I feel like the comeback at the 2020 US Open saved Dominic Thiem's legacy. If he doesn't complete the comeback, I feel like we'd be looking at not only Thiem, but Zverev, a lot differently. If Zverev holds on to win that match, their career comparison aren't even close, with Zverev having a clear advantage over Thiem. We'd also be questioning Thiem's mental toughness, instead of Zverev's (especially what would come later, with how Zverev was able to come back from his injuries a lot better than Thiem).