The whole Andy Murray team has to be extra cautious during the Scotsman's matches, reveals fitness coach Matt Little.
Little is a longtime fitness coach of the 30-year-old.
Murray, who has always been exceptionally prepared, collaborates with Little for 10 years.
The three-time Grand Slam champion has always been showing lots of emotions during his matches.
The 30-year-old's on-court rants from the past include stony and cold glares to his box.
"Being in the players’ box is a white-knuckle ride. The stress in that scenario is just incredible," Little told on tennis coach Kris Soutar's podcast. "When he is taking the balls from the ball boy and at the change of ends, you're not talking, it's only eye contact. And my God we have had a few times when that hasn’t happened and that's caused some issues
"You have to have a poker face when the player is looking at the box. We have had times in the box where I have snapped back at Andy because I had brought my own issues into the box.
"He has had a pop at the box and I have had a pop back at him which is never a good idea. It worked once but it didn't work the rest of the time and it's an awful feeling when you lose control of your own emotions in there because then you have let the player down.
"You're not there to be another source of stress, there's enough with a couple of million people watching and 10,000 people in the stadium.
Little has been careful not to lose his cool and composure during the rants.
"So many people have said to me down the years, 'Oh if I was in that box I would tell him where to go' and you think that’s wrong," Little revealed. "If you did do that you would be there five minutes, you would only be there for one match.
"Tell him where to go and walk out the box? I don’t think so."