Answer
Daniil Medvedev, the eventual champion, faced Aslan Karatsev in the semifinals of the 2021 Australian Open. Karatsev, a qualifier ranked 114th in the world at the time, had made a surprise run to the semifinals, defeating seeded players Grigor Dimitrov and Felix Auger-Aliassime en route. Medvedev, on the other hand, was the fourth seed and had not dropped a set prior to the semifinals.