NEW YORK — Daniil Medvedev earned his first major title by beating Novak Djokovic at his own game in a stunning upset Sunday in the US Open men’s final. Medvedev denied Djokovic a victory that would have given him the first calendar-year Grand Slam in men’s tennis since 1969, beating the No. 1-ranked player 6-4, 6-4, 6-4. Medvedev, a 25-year-old from Russia, lost to Djokovic in this year’s Australian Open final and to Rafael Nadal in the 2019 US Open final. Djokovic made a lot of mistakes in the match and admitted as much afterward. But a lot of his issues had to do with Medvedev, who used his 6-foot-6 frame to chase down everything and respond with seemingly effortless groundstrokes — much the way Djokovic wears down foes — and delivered pinpoint serving. Medvedev won 20 of his first 23 service points, establishing a pattern. He finished with 16 aces and 38 winners in all, 11 more than Djokovic. After overcoming multiple double faults on match point, Medvedev finally finished the job, then toppled over to the court on his side — a tribute to the “dead fish celebration” in the famous soccer video game FIFA. Medvedev lost only one set in the entire tournament.