Daniil Sergeyevich Medvedev is a Russian professional tennis player. He has been ranked as high as world No. 1 in men's singles by the Association of Tennis Professionals (ATP), and is the current world No. 4. Medvedev has won 20 ATP Tour singles titles, including the 2021 US Open and 2020 ATP Finals. Medvedev defeated world No. 1 Novak Djokovic in the final to deny him the Grand Slam. In the latter, he became the only player to defeat the top three ranked players in the world en route to the year-end championship title. He has also won six Masters titles and contested six major finals. His six Masters titles all came in different venues, making him only the sixth player to win Masters titles at six different venues.

The ATP Masters events, known as ATP Masters 1000 tournaments since 2009, are an annual series of nine tennis tournaments featuring the top-ranked players on the ATP Tour since its inception in 1990. The Masters tournaments, sitting below the Grand Slam tournaments and the year-end championships, make up the most coveted trophies on the annual ATP Tour calendar. In addition to the quadrennial Summer Olympics, they are collectively known as the 'Big Titles'.