"When you really have an injury, it's impossible to win a tournament like this" - Rafael Nadal

Rafael Nadal scored a straight-sets win over Fabio Fognini on Monday, to advance to the quarterfinals of the Australian Open where he will meet Greece's Stefanos Tsistipas. But much of the talk around the Spaniard in the first week has been centered around his iffy back.

In his first couple of press conferences, Rafael Nadal insisted that the back injury which forced him to pull out of the ATP Cup hadn't completely healed yet. But after Monday's match, the Spaniard declared that the first set against Fognini was the highest level he had exhibited at this year's tournament.

When asked for his views on playing through an injury, Rafael Nadal asserted that it is a personal choice which depends largely on the tournament and the time of the year.

"It depends what kind of injury you have," Rafael Nadal said. "You have something broken, I think you have a strain or your abdominal - for example, I did it in the past, and you make mistakes because it's impossible to know exactly what's going on when you are competing."

Rafael Nadal further claimed he is far more careful about not playing with serious injuries at this stage of his career, since it is next to impossible to win a Grand Slam that way.

"You need to find a balance, but of course at this point of my career, if there is a big chance to increase something very important, probably I will not play," Rafael Nadal said. "Because for me the happiness is much more important than give me a chance to win. And at the same time, if you are bad, you will not win. That's clear."

"If you have some pain and it's not putting you in a situation that limits you, the movements, maybe you can find a way," he added. "But when you really, really have an injury, it's impossible to win a tournament like this."

"Wasn't a smart decision" - Rafael Nadal recalls his struggles with an abdominal injury at US Open 2009

Rafael Nadal

The subject of injury has dominated the discourse in the tennis community of late, with Novak Djokovic also suffering from an abdominal injury. Djokovic initially suggested he had suffered a muscle tear during his third-round win on Friday, but the Serb returned to defeat Milos Raonic in the fourth round on Sunday.

After his win, Djokovic told the press he didn't want to divulge the exact details of his injury since he was still in the tournament. The World No. 1 mentioned that he was unsure of the extent of the injury since he was on a high dose of painkillers, but added that there was a risk of further aggravating it by continuing on.

In his press conference on Monday, Rafael Nadal cited his own personal experience with an abdominal injury at the 2009 US Open, which worsened as the tournament wore on. Nadal claimed he was willing to take the risk since it was the end of the season and he had a one-month window to recuperate after the tournament.

"I remember in the US Open 2009 that I started the US Open with a strain, I think, here in the abdominal," Nadal said. "I started with 6 millimeters or so of strain and I finished the tournament, I lost in that semis against Del Potro and I finished the tournament with 26 mm."

"Of course it wasn't a smart decision," he added. "Well, it depends what you have later after the US Open. I feel that if I have to rest for one month or something, it was not a disaster for me."