McNally told the Tennis Channel she went to the U.S. Tennis Association's National Campus in Orlando for about 12 days so she could train on clay tennis courts before traveling to Europe. The French Open is the only Grand Slam tournament held on clay, at Paris' Stade Roland-Garros.
"I really like playing on red clay," McNally said. "I never grew up playing on red clay like a lot of these people."
Ahead of Saturday's singles final, she also said she looked forward to competing against Gauff.
"To play another American is awesome because you know that no matter what, there's going to be an American winning and that's really good for U.S. tennis."