Samantha Stosur's toughest opponent is in her head, not on the other side of the net.
Her long-time coach David Taylor says there's no physical reason why Australia's best female tennis player is struggling this year.
But there's a mental explanation.
"There's physically no problem at all but no doubt she's having some problem dealing with the expectation and pressure of being a top player," said Taylor of the world No.6 and 2010 French Open finalist.
"Her year hasn't been what she'd hoped but gee she's trying hard to get on top of it."
Stosur, 27, stamped herself as a genuine major title contender with her impressive results last year, especially on clay, but this year hasn't had the same impact.
Taylor mentioned players like former world No.1s Dinara Safina and Ana Ivanovic, who saw their rankings plummet as they struggled with "being the hunted rather than the hunter".
"I wouldn't put her in that category ... but her results haven't been that of a top player and that's something she's trying to address."
He said Stosur felt "discouraged" by her lack of form - she hasn't made a quarter-final this year or beaten another top 10 player since last October and lost her second match when defending the clay court title in Charleston last week.
"A bit of doubt's set in and she simply needs to win some close matches against some good players," said Taylor
Rather than play Australia's Fed Cup tie against Ukraine in Melbourne this weekend, Stosur has elected to go to the WTA tournament in Stuttgart, Germany, with her eye on another big run at next month's French Open, where she must defend a stack of ranking points.
Taylor believed winning under pressure in the Fed Cup, where she has a great record, may have helped her cause but said it was her decision.
"She needs a good result in Stuttgart now, there's pressure on.
"If she doesn't have a good next month that will really affect her chances to do well in Roland Garros.
"I can't see why she can't get on top of this, it just takes a good tournament."