Brisbane - Germany's Alexander Zverev said he felt in top shape for 2020 Thursday despite only starting to hit balls a week ago after an off-season curtailed by a lucrative exhibition tour.
The 22-year-old only won one title last year, in Geneva, not quite taking the step up that many had predicted as he slipped from fourth to seventh in the men's tennis rankings.
But Zverev remains a big drawcard and he finished 2019 playing a five-stop exhibition tour of South America and China with Roger Federer.
Although the tour meant a shorter off-season than normal, Zverev insisted it made little difference.
"I mean, still I think I had a good off-season. It was a little bit different. It was shorter this year, for sure," he said at the ATP Cup team event in Brisbane.
"I only started playing tennis a week ago, pretty much, so I don't have a lot of tennis practice yet, which I will build up.
"But I feel good. I feel pretty fit again. My physical (condition) was never really my problem. It was in the beginning of my career, but in the last one, two years it's never been a problem.
"I know I can last matches, I know I can play longer than most guys."
While Zverev is confident about his on-court stamina, he admitted he could have played better last year and wants to put that right this season.
"For me I need to get my tennis back a little bit and kind of have a fresh start as well," he said.
"Obviously, the last year I finished number seven in the world. I had good tournaments, but it was still not the year that I wanted to have and I hope I can kind of improve this year."
Zverev is playing the inaugural ATP Cup under the captaincy of German great Boris Becker and he is confident they will do well, despite being in a tough group with the Nick Kyrgios-led Australia.
Under the tournament format, 24 nations are split into six round-robin groups across Brisbane, Perth and Sydney with only eight teams qualifying for the knockout phase.
"We have a good team. We have top doubles players in the world. We have myself, Jan-Lennard (Struff), Mats (Moraing), who are great singles players," he said.
"So we want to give ourselves the best chance to win and I think Boris can play a big part in that.
"He can play a big part in what he will say on the bench, the energy that he has. I mean, he is one of the most iconic sportsmen in German history."