German tennis star Alexander Zverev has been criticised for his lengthy second-serve routine at the U.S. Open final, with his opponents calling for a change in the rules.

The controversy came after Zverev’s 6–3, 7–6(2), 5–7, 6–2 victory on Sunday in New York against Ben Shelton of the U.S. On his second serve of the game, he bounced the ball 25 times before serving.

The move frustrated Shelton, and the American demanded a change from tennis associations on the ‘stupid’ rule.

The rule states that a player has 25 seconds to serve after a point. If the first serve is a fault, the player gets a second serve, but there is no separate 25-second limit for it.

Shelton said he was told to stay in the receiving position, even though Zverev could take another 20-30 seconds before serving, and he expressed his frustration and called for a review of the rules before a second serve.

Zverev responded to the criticism, saying that it was a bit extreme for the ball-bouncing routine.

He said, “But I am still always within the time frame, so at the end of the day, you can do whatever you want within the actual 24 seconds of serving.

“But it was a bit extreme, I have to admit that.”

His other opponent, Russian tennis star Karen Khachanov, said that he faces a similar issue, which he described as annoying, adding that it makes it stressful for the receiver to know when to prepare for the next serve.

This has prompted calls for a rule limiting how many times a server can bounce the ball.