It's more a tennis problem than a mental problem. The transition is difficult. It depends how much time you have. Playing on grass can sometimes be a bit of a lottery.
Rafael NadalFor sure, with golf it's not a physically demanding sport like tennis. That's what makes tennis great - you combine both things. It's a very mental sport and at the same time can be dramatically physical. But I do admire the mentality of sport more than the physicality because physical performance is much easier to practice than mental performance.
Rafael Nadal