Novak Djokovic delivered a lesson in Grand Slam tenacity to Learner Tien in the first round of the U.S. Open on Sunday as he battled past the American teenager. https://www.japantimes.co.jp/sports/2025/08/25/tennis/novak-djokovic-us-open-start/?utm_medium=Social&utm_source=mastodon #tennis #usopen #novakdjokovic #arynasabalenka #emmaraducanu