Patrick taking a bite of the churro and letting Art take one was unscripted. Josh O'Connor was starving and it was the first time he ever had churros.
To prepare for her role, Zendaya spent three months with pro tennis player-turned-coach, Brad Gilbert.
The New Rochelle Umpire is played by Darnell Appling, an assistant to Zendaya. To prepare for his role, Appling took professional umpire lessons.
Austin Butler and Timothée Chalamet were considered for the role of Art Donaldson before Mike Faist was cast.
Though the tennis match in the modern day takes place in one afternoon, it was filmed across three weeks at all times of day, in full sun and under clouds, with temperatures ranging from the forties to the nineties (°F). There was even one day a mass pollen release by some nearby trees that tinted the whole set (and all the people on it) yellow, which wasn't removed until rain fell over the next few days of filming.