It's not as if either Roger Federer or Rafael Nadal needs to ask directions entering this year's U.S. Open. But the two best players of this generation suddenly are facing uncharted territory - Federer in pursuit of revised motivation, now that he has won more major titles than any man in his sport's history, and Nadal seeking sufficient physical soundness to allow a return to his punishing style.
Federer's new theme is change-of-life stuff: Recently married, the father of twin girls, might his tennis, at 28, be a lesser priority? Nadal's storyline is about physical uncertaintly, the frightening possibility that, though only 23, his potential greatness might already be compromised.
Federer "has got to be a little human, to be let down a little," said John McEnroe, the No. 1 from a previous generation. "Of course the pressure is off; he's broken the record [with a 15th major championship won at Wimbledon last month], he's the all-time great. But any human being in this situation, even Roger, after making the final in Australia and then getting those two big wins [at the French and Wimbledon], as he gets older he's going to have to pare down a bit.
"It'll be harder for him to maintain that No. 1 ranking. Nadal had taken it away and now these young guys, the Andy Murrays and Novak Djokovics, have looked ready to step in . . . "
Nadal, meanwhile, is dealing with a too-soon brush with mortality. Finally ascending to No. 1 a year ago, Nadal was upset by Robin Soderling in the French Open - ending his four-year title run there - skipped Wimbledon because of tendinitis in both knees and now is attempting to regain his health on the tour's most demanding surface, hardcourt.
"Nobody knows except Nadal how good he feels," said Patrick McEnroe, John's younger brother whose various tennis hats include serving as the U.S. Davis Cup captain. "Watching him [in his return to action in Montreal two weeks ago], he looked healthy. But that doesn't mean he's 100 percent. There has to be some doubt in his mind; he's healthy but is he healthy enough to play five sets, then four sets two days later? Can he get back [to top form] by training an hour or two a day, as opposed to the four or five hours he's done in the past?"
Nadal's forced absence left the opening for Federer to regain the top ranking and, more recently, allowed Murray to slip past him into the No. 2 spot. Essentially, though, Federer and Nadal have returned to previous roles that long had defined their rivalry, with Nadal as the troll under Federer's bridge.
For 160 consecutive weeks of Federer's record 237-week reign as No. 1, Nadal was the lurking No. 2. And, more than that, Nadal won 13 of their 20 head-to-head matches, including their last three meetings in Grand Slam finals. More than anyone else, Nadal has appeared most capable of holding Federer's feet to the fire.
But now what? The McEnroe brothers see essentially the same players - the stylish, make-everything-look-easy Federer and the grinding, relentless muscleman Nadal.
"It's hard to imagine," John McEnroe said, "that Roger wouldn't win at least two, three, four more [major tournaments]. That seems almost impossible, but with Roger, it's difficult to say there's anything he couldn't do."
Patrick expects Federer to play "three, four more years, but I don't think he'll be able to dominate; he hasn't really, the last couple of years, which makes it unbelievable what he's pulled off the last two months. To be perfectly honest, the biggest factor in how many more majors Roger wins is Nadal, and how healthy he is."
Whatever path each man takes, they seem bound to meet, head on, in the near future.