"But it's very difficult, I can tell you I played the Czech Open a few times and it's very difficult just to go on to a scene where the course is prepared differently when the greens are fast and he's not used to it and they're hard as a rock and he's not used to it"

Ivan Lendl is referring to the trouble of playing in a tournament such as the Czech Open. He has experienced it direct and can vouch for the difficulty of playing on a course that is unknown to the gamer. The greens are frequently quick and hard, making it tough to adapt to the conditions. This can be especially challenging for gamers who are not utilized to playing on such surface areas. Lendl is emphasizing the trouble of playing in a tournament such as the Czech Open, and how it can be a challenge for gamers who are not utilized to the conditions. He is likewise highlighting the importance of being able to get used to various courses and conditions in order to succeed in competitions.