Karatsev had one break point for a 4-0 lead against Schwartzman in the first set, which saw the Russian qualifier lose just three first-service points and hit 13 winners. After saving two break points at 0-1 in the second set, Karatsev didn’t blink and struck back-to-back forehand winners to seal the set.
https://www.atptour.com/en/news/karatsev-schwartzman-australian-open-2021-friday