Even top tennis stars have their doubts

One might imagine that a tennis professional, accomplished enough to be among the elite performers in the U.S. Open field, would be beyond insecurities about his or her playing abilities. Not so. Among major-tournament champions, as well as younger athletes climbing the rankings ladder, expressions of doubt are not uncommon.

No less than Novak Djokovic, the world's top-ranked player whose Wimbledon title last month was his seventh in a Grand Slam event, arrived at Flushing Meadows this week kidding that his recent discomfort on the court might require him to train with "two rackets. I'm going to play with two rackets" to improve his Open chances. Since Wimbledon, Djokovic has won only two of four matches and has admitted being "irritated a little bit. Let's be honest: I don't enjoy playing bad."

Wimbledon's 2014 women's champion, Petra Kvitova, left last week's first-round loss at the Open tune-up tournament in Mason, Ohio, admitting, "I can still find moments when I really don't know what's happening out there."

Even Roger Federer, with more major-tournament titles (17) than any other man in history, recently acknowledged that "the fear is always there," that all-important self-confidence is an elastic thing, stretching to nothing-can-go-wrong certainty, then snapping back suddenly into moments of confusion.

"You know, confidence is a weird thing," said Ana Ivanovic, a former No. 1 who won the 2008 French Open but has been as far as a Grand Slam quarterfinal only twice since. "It goes and comes really fast."

The reality of dueling with fellow pros of virtually equal skill obviously plays a central role of match results, and therefore players' moods. As Djokovic reminded, "You can't win them all." Still, so much of players' well-being remains in their own heads.

"I don't know. I think you always feel up and down a little bit about the game," said former No. 1 Caroline Wozniacki, whose ranking stagnated a bit around No. 10 the past two years before her recent surge this summer.

Some days, 19-year-old Madison Keys said, she feels as if she has figured things out, especially since winning her first pro tournament in Eastbourne, England, this summer and reaching the highest ranking (27th) in her six years on tour. But, she added, "There are obviously still some days when I just kind of think, 'What the heck am I doing? I should not be playing tennis right now.' "

Knowing that she could put together a solid week of competition at Eastbourne, Keys said, "and continuing to try to do that, and not want to jump off a bridge on the days that it's not working -- that's definitely been good for me. I'm working on it. Still no promises. And some days I'm better at it than others, and that's definitely part of the next jump."

It may or may not reassure her to hear 14th-year pro Maria Sharapova, whose 2014 French Open title was her fifth career major championship, reflect on the sometimes uneven self-belief journey. "When you're young and every experience is new and different," Sharapova said, "it's just a learning experience, really, and you can't really take anything from the past, because you haven't been in that position before.

"As you grow older and you've been in different situations, whether winning or losing or going through tough moments or great moments or confident rides, you know how that feels."

Meanwhile, the process goes on, bumpy at times and exhilarating at others.

"Some people have to work at technique," said 18-year-old Taylor Townsend, the world's top-rated junior player in 2012 and now in her second year as a pro. "Some people have that mental edge. Some people understand the game at a younger age or understand their game.

"For me, personally, I'm having to learn myself as well as the game of tennis. So it's a lot. But constantly learning, that's the fun of it."