LONDON — Alexander Zverev claimed the biggest title of his career on Sunday, winning the ATP Finals with a 6-4, 6-3 upset of Novak Djokovic. Zverev, 21, became the youngest champion of the season-ending event since Djokovic claimed the first of his five titles a decade ago — also at age 21.
But Zverev is not ready to make any comparisons.
“Oh, my God,” said Zverev, who also became the first German winner since 1995. “I’ve won one. He’s won five. He’s won, I don’t know what, 148 titles more than me. Let’s not go there for now.”
Djokovic, the top-ranked men’s player, was attempting to tie Roger Federer’s record of six titles in the event. But he followed the same path as Federer, who lost to Zverev in the semifinals at the O2 Arena on Saturday.
Djokovic’s serve had not been broken in the tournament until the final match. Zverev did it once in the first set and three times in the second, completing the victory with a spectacular backhand winner up the line.
For his part, Djokovic, who ended a two-year Grand Slam title drought by winning Wimbledon this year, noted the similarities in his and Zverev’s career trajectories. “Hopefully he can surpass me,” Djokovic said.
Both players began the match in the same form in which they had earned straight-sets semifinal wins a day earlier, with few points going against the server.
It was Djokovic, who had lost just two of his previous 37 matches and had defeated Zverev in the round-robin stage, who began to feel the pressure when he made two straight forehand errors to give up his first break of the tournament, for 5-4.
Fans gave Zverev an ovation as he stepped up to serve for the set, and it seemed to inspire him. Three straight aces brought up three set points, the second of which he took when Djokovic sent another forehand long.
“From 4-4 in the first set, my game really fell apart,” Djokovic said.
A 26-shot rally brought up another break opportunity in the opening game of the second set, and although Djokovic saved it, Zverev won another lengthy exchange moments later with a forehand winner to go up by 1-0.
With the biggest win of his career in sight, Zverev began to show some nerves. Although he is the only active male player outside the so-called Big Four — Djokovic, Federer, Rafael Nadal and Andy Murray — who possesses at least three Masters titles, Zverev has reached only one Grand Slam quarterfinal.
Two double faults and two backhand errors gave Djokovic an immediate break back, but Zverev quickly refocused to win a 28-shot rally on his way to breaking in the next game.
From there he remained solid on serve, before ending with a flourish. A backhand winner on the run drifted past the helpless Djokovic, and Zverev sank to the ground in tears.
“This trophy means a lot, everything,” Zverev said. “You only have so many chances of winning it. You play against the best players only.”