World number four Alexander Zverev has revealed which player he considers "perfect" in tennis, while mentioning his goal for the new year.
Zverev enjoyed the most successful year of his career in 2017 as he won five ATP titles, his first ever Masters 1000 title and reached a career-high world number three ranking.
The 20-year-old was no doubt helped by the absence of many injured stars such as Novak Djokovic, Andy Murray and Stan Wawrinka, but still managed to end the year impressively as the number four-ranked player in the world.
However, his performances in the Grand Slams left much to be desired as the German's best performance was a round of 16 exit at Wimbledon to Milos Raonic. He is also yet to beat a top 50 player in a Grand Slam as he revealed his goal is simply to do much better in the major events.
"I'm the world number four, therefore I hope to do better at the Slams this year," Zverev said on the ZDF Sports Studio German programme via Tennis World USA.
The discussion then turned to whether there was a "perfect" player in tennis, and while Zverev initially claimed there was none, he soon changed his mind.
"There's no one 'perfect' in tennis," he added. "Except maybe when we talk about Roger [Federer]. You could say he's perfect."
Roger Federer enjoyed a career renaissance in 2017 as he won six titles, including two Grand Slams, to end the year as the world number two at 36 years of age.
Zverev notably faced the Swiss ace three times in the calendar year as he lost twice but managed to defeat Federer — albeit carrying a back injury — in the final of the Rogers Cup in Montreal.
"For me, Zverev, I think," Safin revealed. "Plus he has a good coach, [Juan Carlos] Ferrero. He was a good player and has done good work with him.
"He is number four in the world, so he can manage, so let's see. The rest [of the young stars], we'll wait for next year."