Winning the mind game in a tennis match is as important as scoring points when it comes to the cauldron of competition on court.
Success in tennis is not only about physical strength; it is about mental mettle too.
"Mental toughness is what separates the ones at the top," Judy Murray, mother and former coach of 2013 Wimbledon champion Andy Murray, tells the BBC.
"There are a lot of good players out there, but it's only the tough that survive."
Tennis is an individual sport where, in the singles game, two minds and two bodies duel across a net.
This intense pressure is heightened by the scrutiny of the grandstands and TV audiences around the globe.
There is also a high percentage of "dead time" relative to when a player is hitting the ball.
This space between the points and games provides plenty of opportunities for negative thoughts to trip up the mind and blunt the competitive edge.
So, what might we really find if we peered inside the mind of a top tennis player?
"Someone that can focus and deal with adversity and the ups and downs of a match," says Australia's two-time grand slam champion Lleyton Hewitt.
"There are only one or two points that can turn a match, so you have to be able to handle the positives and negatives of what happens out there."
American No. 1 John Isner adds with a smile: "You might see a lot of messed up things!
"There's a lot of anxiety in tennis, especially before a grand slam when you want to get off to a good start."
Dealing with the mental stresses and strains of tennis is complex.
Rituals and routines
Pre-match coaching advice followed by courtside support from loved ones can help but only the player can truly master the mind and emotions in the heat of a match.
Many of those at the top of the game have developed rituals and routines to help them keep a cool head on court.
Novak Djokovic is known as a habitual ball bouncer, Maria Sharapova delivers a distinctive grunt while Rafael Nadal likes to adjust his shorts.
It is just these kinds of idiosyncrasies that have helped them become multiple grand slam winners.
"Players have to be the masters of their own destiny in terms of picking themselves up if they lose a point, and finding the motivation to keep going," says Rachel Newnham, the performance lifestyle advisor for British players at the Lawn Tennis Association.
"Routines, visualisation and understanding what to do in those moments when they choke or get tight are important.
"This is an area where a sports psychologist can use certain techniques to help a player."
When he was 17-years-old, Roger Federer turned to a sports psychologist to stop his tennis tantrums and the Swiss ace now has 17 grand slams to his name.
Japan's 2014 US Open finalist Kei Nishikori also believes working with a psychologist has helped improve his game.
"It's made me very strong mentally," he says. "You have to enjoy the match, try to stay focused, even if you are losing, and to always see a goal.
"A player has to think a lot during the match. We don't get coaching on court so the top guys are very smart."
This on-court intelligence combined with more intangible qualities can also help determine success or failure.
The first big stars of the Open era - names like Bjorn Borg, Jimmy Connors and John McEnroe - turned tennis into show business.
Connors was the fist-pumping warrior, rousing himself to seemingly impossible comebacks, Borg was dubbed the "Iceborg" for his composed and clinical play, which contrasted totally to the fiery feistiness of McEnroe.
The trio understood that allying their own unique personalities to an incredible competitive drive was vital to success.
"Being a competitor is a quality you cannot learn, you either have it or you don't," says Carlos Rodriguez, who coached China's double grand slam champion Li Na and Belgium's seven-time grand slam winner Justine Henin.
"Many times I talked about it with Justine and Li. I cannot help another player go to the extra dimension that Li Na did, that Justine did, that Serena Williams does now.
"Why? Because they are champions and they are something more than the others.
"It's not a behaviour, it is a state of mind and something that was maybe born a long time ago in their childhood."
All in the mind
Toni Nadal has coached his nephew Rafael to 14 grand slam titles and agrees the root of that success was planted during his childhood.
"I thought that Borg and McEnroe were special people," he tells he BBC. "I saw my nephew with good talent, but a normal guy, not good like McEnroe or Borg.
"When Rafael was young I thought it would be impossible to be so good but you need a good mind and good work, and then you can be a good player.
"The most important thing in this life - in all things, not just tennis - is to have the ability to learn and this is what I think Rafael has."
A willingness to learn about the mental and intellectual demands of the game is being impressed on the rising stars of British tennis.
"It's something we're trying to work on with our juniors," explains Newham. "To give them an idea of what type of attitude, characteristics and values they need to make it as a professional tennis player.
"Very few understand what it takes to be successful. Determination, focus and having the drive and ambition to always want to be the best are important.
"But other qualities, like a good level of self-awareness and understanding, are also incredibly important.
"Some tennis players are cool, calm and collected whereas for others, having a little bit of fire and passion works."
It could just be that success in tennis is all in the mind.
Reporting by Sarah Holt