Serena Williams was in championship mode ahead of the U.S. Open Final -- and that means she didn't have time to chat ... especially for silly questions about Meghan Markle.
The tennis icon left her hotel Saturday with a look of determination on her face as she boarded a waiting SUV, which was ready to drive her to the Billie Jean King Tennis Center in Queens, NYC ... where Serena is facing off against Canadian Bianca Andreescu in the Women's Singles championship later. Paps were standing by, but SW made no time for them.