Alexander Zverev clinched a potential breakthrough into the ranks of the elite as he stunned Novak Djokovic 6-4, 6-3 to win his first major trophy at the ATP Finals.
The 21-year-old German ranked fifth pounded down 10 aces against the world No.1, with Djokovic held to just one.
Zverev is the youngest player to win the year-end title since Djokovic himself in 2008; the last German to reach the title contest was Boris Becker who won it in 1995.
Djokovic, claimed Wimbledon and US Open titles in his comeback to form this season after an elbow injury which tormented him for a year, ens the season atop the rankings.
“Right now I really can’t describe it,” Zverev said as he lifted the trophy. “I’m unbelievably happy, obviously it’s the biggest title that I’ve ever won.”
The youngster was playing the season wrap-up for a second straight edition but was halted in the group stages.
His defeat of Djokovic came a day after he put out Roger Federer here.
“Obviously it’s quite astonishing, winning this title, beating two such players back-to-back, Roger and Novak, in semi-finals and finals.
“It means so much. I’m incredibly happy and incredibly proud of this moment right now.”
Djkovic had been bidding to match Federer on six year-end trophies and came to the court after winning 35 of his previous 37 matches.
“I’m really happy for him. I mean, obviously it’s not great to lose a tennis match, especially in the finals of a big tournament,” Djokovic said.
“I’m quite disappointed with my game. But I’m happy that he won the big title because we have a really good and friendly relationship.
“We reside in the same place (Monte Carlo). We train a lot. We see each other a lot. He comes from a really nice family.
You could see how much it means to him. Obviously he deserved it.” Zverev called the title “obviously the biggest title of my career so far.
“This trophy means a lot, everything, to all the players. You only have so many chances of winning it. You play against the best players only. How I played today, how I won it, for me it’s just amazing.
“Everyone knows how good of a tennis player you are,” he told Djokovic in the trophy ceremony. “I want to mention how good of a person you are. We’ve had a lot of good talks on life.
“I appreciate you letting me win the title today,” the German joked.
The winner finished the season with a leading total of 58 match victories.