Tommy Haas acknowledges struggling after a serious injury isn’t something uncommon but also warned Alexander Zverev it could quickly become ugly for him if he fails to rediscover his best tennis. Zverev, a former world No 2, tore several ligaments during his 2022 French Open semifinal match againstRafael Nadal.

Since returning to tennis at the start of the 2023 season, Zverev has been struggling with his form and results. Zverev, now ranked at No 22 in the world, is in danger of exiting the top-100 if he loses early at the Rome Masters and French Open where he has semifinal points to defend.

“Zverev has had a lot of ups and downs for a long time, which is quite normal after such a long injury. But at some point he has to flip the switch. He has to defend points for the next three or four weeks. Otherwise he falls out of the top 30, 40 or 50 in the world.

Then the strong opponents threaten early in the tournaments. This situation is new to him. If he’s in top form, feels good and has confidence, there are only four or five players in the world who can beat him,” Haas told Bild Sport.

Zverev, who turned 26 last month, is not anymore just a young and promising star. With the arrival of young stars such as Carlos Alcaraz, Holger Rune and Jannik Sinner, winning a Grand Slam has become an ever bigger challenge for Zverev.

“It is becoming increasingly difficult for him to achieve his last major career goal – winning the Grand Slam tournament. The next star is here in Alcaraz. And you still have Tsitsipas, Medvedev, Rune, [Jannik] Sinner, [Lorenzo] Musetti.

The Americans come with [Taylor] Fritz, [Tommy] Paul and [Frances] Tiafoe. The competition never sleeps,” Haas added. It remains to be seen if Zverev can find some form ahead of the French Open.