Final answer:
Daniil Medvedev is the current Men's Singles US Open champion, and Emma Raducanu is the reigning Women's Singles champion, both winning in 2021.
Step-by-step explanation:
The current Men's Singles champion of the US Open is Daniil Medvedev, who won the title in 2021. On the Women's side, Emma Raducanu is the reigning champion as of the 2021 US Open. Both players achieved significant milestones with their victories. Medvedev's win marked his first Grand Slam title, while Raducanu made history by being the first qualifier ever to win a Grand Slam, doing so in spectacular fashion without dropping a set.