Alexander Zverev fears running out of time as 25-year-old 'not happy' with tennis career

Alexander Zverev has admitted he may be running out of time in tennis if he is to get the success he wants from his career. The German, 25, is currently playing the Madrid Open, where he beat Marin Cilic in the first-round before a walkover win against Lorenzo Musetti. He'll now play Felix Auger-Aliassime in the last eight.

However, the world No 3 continues to battle the perception that he's yet to fulfil his potential on the big stage. His only Grand Slam final to date came at the 2020 US Open, where he was beaten in five-sets by Dominic Thiem.

He has reached the final-four stage at both the Australian and French Open, but has never been past the last 16 at Wimbledon. From his 19 career titles thus far, his most significant came in Tokyo last summer, winning Olympic gold by beating Karen Khachanov in the final.

But the German star has admitted he's unhappy with where he's at with his game, and conceded he was "no longer the youngest" in terms of tennis pro's: "A tennis player's career is limited in time. When you're young you think: 'Oh, I still have enough time, I'm more of a hunter than a hunted man. That has changed," he told EurosportLink.

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Zverev has been embroiled in off-court controversies during his career, and this year sparked outrage at the Acapulco Open. He was defaulted from the tournament ahead of his match against Peter Gojowczyk for violently and repeatedly hitting the umpire's chair with his racket after his loss in doubles.

And he admitted he now needed to "devote my entire concentration to tennis," adding: "I've made a lot of mistakes in my life, on the tennis court but also off it. But there are always