Rafael Nadal backs Jannik Sinner, as Roger Federer highlights what "needs to be answered" in doping case

As Jannik Sinner prepares to play his US Open quarterfinal against 2021 champion Daniil Medvedev, two of the sport’s biggest names have weighed in on the way the Italian’s recent doping case was handled.

The world No. 1's run in Flushing Meadows has been mired in controversy after he revealed last week that he twice tested positive for trace amounts of clostebol back in March and was ultimately exonerated. The news sparked fierce debate in the sports world, coming 24 hours after his Cincinnati Open victory and in the build-up to the last Grand Slam of the year.

Now, Rafael Nadal and Roger Federer have come out in agreement that Sinner didn't act intentionally—echoing the "No Fault or Negligence" ruling from the International Tennis Integrity Agency (ITIA).

Read More: “I’m just a simple tennis player”: At US Open, Jannik Sinner insists fair treatment in anti-doping saga

Nadal went as far to assert he doesn’t believe Sinner benefited from a double standard during the process that followed.

“I trust that he wasn’t punished because those who judged this case determined quite clearly that there was nothing to punish,” the 22-time major winner stated Monday in a Spanish interview with El Hormiguero talk show.

“I don’t believe the sentence has anything to do with him being No. 1 in the world.”

The inconsistency, potentially, that he didn’t have to sit out while they were not 100% sure what was going on... I think that’s the question here that needs to be answered. —Roger Federer

Swiss champion Federer, however, grasps why others may not agree with Nadal. Beyond forfeiting points and prize money from Indian Wells, the reigning Australian Open champion was cleared to continue competing by the ITIA.

The news of his positive tests did not come out until the day after he won the Cincinnati Open, on August 20.

Read More: “Should be gone”: Nick Kyrgios hits out at "No Fault" finding in Jannik Sinner anti-doping case ahead of US Open

“I understand the frustration of, ‘has he been treated the same as others?’ And I think this is where it comes down to,” Federer said on the U.S. morning show Today in advance of his scheduled appearance Tuesday night at Flushing Meadows.

“The inconsistency, potentially, that he didn’t have to sit out while they were not 100% sure what was going on... I think that’s the question here that needs to be answered.”

By contrast, Nadal appeared to conclude that’s already happened.

“In the end, justice is justice, and I believe in justice," the Spaniard said. "I believe in the bodies that have to make decisions and that they do it based on what they believe is right.”

It's a sentiment that Federer also encouraged, “We need to trust the process as well of everyone involved.”

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I don’t believe the sentence has anything to do with him being No. 1 in the world. —Rafael Nadal

Sinner was able to successfuly appeal the positive test results by providing the source of the anabolic steroid—an over-the-counter cream purchased by fitness trainer Umberto Ferrara—and identifying how it apparently entered his system—via a cut on physiotherapist Giacomo Naldi's finger during a full-body massage.

During his pre-tournament press conference in New York, the top seed revealed he had fired Ferrara and Naldi after losing his trust.

“Now, because of these mistakes, I'm not feeling that confident to continue with them. The only thing I just need right now, just some clean air,” Sinner said.

The 22-year-old is the youngest man since Nadal in 2008 to reach the quarterfinals at all four majors in the same season.