Roger Federer defeated the defending champion John Isner in the final, 6–1, 6–4 to win the men's singles tennis title at the 2019 Miami Open. It was his fourth Miami Open title, his 28th and final Masters singles title, and his 101st career singles title overall. Federer became the oldest Masters 1000 champion, at 37 years, 7 months and 23 days old, since the series was established in 1990.