MELBOURNE, Australia -- Rafael Nadal has never been as smooth in front of a microphone as Roger Federer, or as comfortable opening a vein and baring his feelings in public. So in the lead-up to the Australian Open, it was telling when Nadal, a man long celebrated for having the most formidable will on tour, didn't dismiss the idea his career's end could be near when he got his version of the retirement question, a topic Federer faces all too regularly these days.

Nadal was asked whether he thought he could win this 2017 Australian Open, and it was a bit surprising when he candidly said, "I don't know."

That prompted a softball follow-up question: What would he be satisfied with here, given he was hurt and barely played the second half of last year? Nadal again unexpectedly took his answer to another deep place: "If I don't believe I can be competitive -- and when I say 'competitive', fighting for the things that I fighting [for] the last 10 years -- I will probably be playing golf or fishing at home. I am being honest with this."

Admitting that kind of doubt or describing the-end-is-near scenarios as you're about to kick off an injury comeback and first Grand Slam campaign in five months is usually not in the playbook of athletes who have done as much as Nadal. He took the top ranking from Federer back when they ruled the game, and looked indomitable doing it. Federer didn't hand it to him. Nadal, and only Nadal, beat Federer at their career heights regularly, often in epic matches, and on every surface.

Roger Federer and Rafael Nadal have combined to win 31 career Grand Slam titles. REINA/AFP/Getty Images

Federer is 35, Nadal is 30, and they've both been hamstrung the past year or two by injuries, especially Nadal. The Spaniard has 14 Grand Slam titles, same as Pete Sampras' total that stood as the men's record until Federer flew by it, extending it to 17. For a long time it seemed a lock that Nadal would join Federer in roaring past 14, too, but Federer has aged far better, even though his major-title drought is nearly double Nadal's (53 months to 31).

Unlike Federer, who's relentlessly buoyant and talks in glass-half-full terms about how taking off the past six months of 2016 for rest and recovery was a "great thing" for him, Nadal's emotional gauge is different, though he too is finally back. A tinge of weariness leaks into Nadal's remarks now, as if he can feel all the miles, workouts and flights unfurling behind him.

Both men had surgery last year: Nadal on his left wrist; Federer (for the first time ever) on his knee. Nadal has spent so many years battling other ailments, primarily with his knees, and only he dwells more on how hard his injury was to take.

Last year, he volunteered that he'd grown tired of playing in pain, and he was not enjoying tennis as much.

"Are you pain-free here?" Nadal was asked two days before he started this tournament Tuesday with an encouraging 6-3, 6-4, 6-4 win over Florian Mayer of Germany.

"I am not injured, no -- but pain-free is a long time ago," Nadal said, smiling only after reporters broke into surprised laughter, knowing how sadly true that is for him.

In December, Nadal decided to add his good friend and countryman Carlos Moya to his team -- an unprecedented change in his support crew, which has always been led by his uncle Toni, his coach dating back to his junior days. Though Toni Nadal originally insisted, perhaps to quiet the tittering, that it was his idea to bring on Moya, after Moya wasn't retained by Milos Raonic, Rafael Nadal has suggested otherwise. He said here in Melbourne that he felt he needed to discuss Moya's addition with his uncle because, "I will never take a decision like this if Toni is not happy."

Nadal cruised through his opening match at the Australian Open on Tuesday. REUTERS/Jason Reed

It was yet more proof that some soul-searching has been going on, and Nadal is looking for something to put some buzz back in everything. Until now, Nadal always been loathe to tamper with much: "My team is the same one since 15 years old," he points out. People beseeched him over the years to tweak his game, forget trying to crush the ball every time and win every point with a 25-stroke rally. Why not end points quicker, be kinder to his body?

He didn't listen.

"I am a person who doesn't like the big changes, who has to be comfortable. I'm not a person who makes decisions like this," he says, snapping his fingers.

While Federer looked at one of his doctors who almost sheepishly suggested he take a three-month break last year to mend, the Swiss replied, "What if I gave you six months?" Nadal is different. He tried to bull his way through the French Open but had to withdraw because of his wrist. He then insisted on playing the Olympics, though he now admits, "I still had a lot of pain. ... I just didn't want to stop again." He was forced to finally call it a year during the tour's fall swing through Asia. "Too much pain," he admits.

Moya, since his arrival, has been direct. He volunteered that Nadal has lost some confidence. He's suggested it's been a little dislocating for Nadal to lose matches and big points that he used to win.

Moya is also on record saying he believes Nadal can get back to No. 1. But the ninth-ranked Nadal, like Federer, doesn't touch that topic anymore -- preferring to emphasize he just wants to enjoy tennis and do his best now that he's back.

Nadal cut his 2016 season short to mend injuries and says he is feeling healthy at this year's Australian Open. Photo by Quinn Rooney/Getty Images

Tuesday's win in the scorching, midday sun was a good start for Nadal. He looks lean and fit, and he moved well against Mayer. Nadal struck the ball well and later declared his wrist problems "are in the past." He played with his usual scowl and look of vise-grip concentration in his eyes as he lined up each ball and violently flung himself into each groundstroke, the same as he always has.

It was, in sum, a very good performance against a tricky opponent on a sauna-like day in which the temperature climbed near 100 degrees.

Finally, Nadal could relax. Much like Federer, who seemed joyous after his win a night earlier over qualifier Jurgen Melzer -- "A special moment, walking back out on the court," the Swiss star said -- Nadal seemed to exhale.

After shaking Mayer's hand near the net, he threw back his head, punched both fists in the air, smiled as he took off his sweat-soaked headband.

"Was great victory for me," Nadal allowed. "The important thing is what can come next."