Alexander Zverev hits the ball back to Albert Ramos-Vinolas during their...

Alexander Zverev hits the ball back to Albert Ramos-Vinolas during their Round 2 match at the 2021 U.S. Open at Arthur Ashe Stadium in Flushing Meadow Park on Thursday. Credit: Errol Anderson

No one is playing better tennis right now than Alexander Zverev.

Zverev is fast emerging as the biggest threat to Novak Djokovic completing a calendar Grand Slam at the U.S. Open. And that fact is emerging as a big problem for the ATP, which with each big Zverev win is under increasing pressure to no longer ignore the allegations of domestic violence made by Zverev’s former girlfriend.

Zverev won his 13th straight match on Thursday, losing just four games in his 74-minute, second-round destruction of Albert Ramos-Violas of Spain . His run started a month ago at the Tokyo Olympics, when he knocked off Djokovic in the semifinal before winning the gold medal in men’s singles. He then followed that by winning the Western & Southern Open, the top tune-up for the U.S. Open.

Three days after the 24-year-old German won the Western & Southern, an article in Slate detailed accusations from his ex-girlfriend Olya Sharypova. The former Russian tennis player alleges that Zverev repeatedly abused her, including an incident in which he tried to strangle her with a pillow and hit her head against the wall in a New York hotel room before the 2019 U.S. Open.

Sharypova, who first made her accusations in a different publication last year, has not filed any criminal charges. Zverev, 24, has repeatedly denied the allegations and before the tournament issued a statement, saying that he would support the introduction of a domestic violence policy on the men’s pro tour.

After his first-round win on Tuesday, Zverev said he planned to push ahead with a legal battle in Germany to clear his name, adding that he would no longer comment on the situation.

"I will not let this sit on me, and that’s it," Zverev said.

I’d bet that’s not it. This is not something that will quietly go away.

It’s possible, however, that some of this could have been avoided if the ATP had a clear domestic violence policy like the ones that have been adopted over the past couple years by the NFL, NBA and MLB.

Rather than rely strictly on law enforcement, the leagues investigate charges of abuse on their own. Players are often suspended with pay while the investigation is underway. The leagues also have established hotlines and counseling to help families in crisis.

The ATP is now being pushed to do the same. In a statement last week, the ATP said that it would begin an independent review of its safeguarding policies, which it said is expected to include recommendations pertaining to domestic violence.

"Abuse has a profound and lasting impact on millions of victims each year," ATP CEO Massimo Calvelli said in a statement. "We believe everyone in tennis should feel protected, fairly represented, and supported in raising concerns. When abusive conduct or allegations are related to any member of the tennis family it can also impact the public’s trust in our sport."

Zverev is not the only player at the U.S. Open dealing with allegations of domestic violence.

Nikoloz Basilashvili is being tried on charges that he physically attacked his ex-wife. Basilashvili, arrested more than a year ago, has played a full ATP tour schedule while his case has made it through the courts in Georgia. The former Soviet Republic only outlawed domestic violence in 2012, and the trial has caused quite a debate in a society where attitudes toward domestic violence are still shifting.

It’s true that tennis players live all over the world, in places that have different laws and different attitudes toward domestic violence. Yet, that makes it only more important that the sport come up with a uniform policy that protects the families of their players and the image of the sport.

Andy Murray, a former No. 1 player who has lobbied for adopting a new policy, thinks doing so will only enhance the image of the sport.

"I just didn’t feel like the sport had much of a sort of stance on it really," Murray said Monday when asked about the ATP’s statement. "So yeah, I guess that’s a step in the right direction."

A late step, but a step no less.