Julia Lemigova

NEW YORK — Tennis great Martina Navratilova proposed to her girlfriend on the big screen of Arthur Ashe Stadium between the U.S. Open men’s semifinals. Navratilova popped the question to Julia Lemigova in the Tennis Channel suite Saturday, drawing a loud cheer from the crowd. “I was very nervous,” Navratilova said later. “It came off. She said yes. It was kind of an …