LONDON - Alexander Zverev has vowed to use the frustration of his ATP Finals exit as fuel to build on his breakthrough year when he returns to action in 2018.
Zverev has emerged as one of the brightest young stars on the ATP tour over the last 11 months, but the German world number three was unable to cap his memorable campaign with a final flurry at London's O2 Arena.
Bidding to become the youngest Tour Finals semi-finalist since Rafael Nadal in 2006, the 20-year-old was bundled out by Jack Sock late on Thursday, as the American eighth seed claimed a surprise 6-4, 1-6, 6-4 victory to snatch second place in the Boris Becker group.
Zverev admitted he had only himself to blame for the season-ending loss.
"Yeah, I choked. It's quite easy. Won the second set 6-1, then I was down 1-4 within 10 minutes where I didn't put many balls in the court," he said.
"When I got back at 4-5, that's one of the worst games I think I played all year. So, yeah, I just choked."
Zverev's coming of age campaign saw him win five titles and become one of just four men to beat Roger Federer this year when he defeated the Swiss great in the Montreal final.
His progress up the rankings has marked him out as the most likely of the current crop of youngsters to translate his talent into Grand Slam titles.
Zverev is desperate to end the dominance of Federer, Nadal, Andy Murray and Novak Djokovic and he has no intention of resting on his laurels in the close-season.
"It's been an awesome year. Still, the end of the year was absolute rubbish for me," he said.
"If I would have played the whole year like I did, by the end of the year I don't think I would have finished top 50.
"Yeah, that's a bit unfortunate. But that's okay. I'm going to go on holidays now. I'm definitely going to enjoy that. Then I'm going to work hard in the off-season.
"I'm going to do three weeks of physical again, then start tennis, just do all the basic stuff again.
"Try to get back to where I was beginning of the year, try to maybe improve even more."
Zverev's training regime will seem that much easier as he recalls the memories of his first two Masters 1000 titles in Rome and Montreal, as well as his maiden appearance at the Tour Finals.
"It's an amazing tournament. It's an amazing experience," he said.