LONDON — Alexander Zverev upset Novak Djokovic to claim the biggest title of his career with a 6-4, 6-3 victory at the ATP Finals on Sunday.
The 21-year-old Zverev became the youngest champion of the season-ending event since Djokovic claimed the first of his five titles a decade ago, and the first from Germany since 1995.
Top-ranked Djokovic was attempting to tie Roger Federer’s record of six titles but followed the same path as the Swiss great, who lost to Zverev in the semifinals at the O2 Arena.
Djokovic’s serve hadn’t been broken all tournament until the final.