Serena Williams isn’t letting US Open practice get in the way of romance. She was spotted with her boyfriend, coach Patrick Mouratoglou, at Bagatelle on Friday. “They were very private,” says a spy. “They seemed to be having a very nice, intimate time.” While the pair stayed until 11 p.m., Williams was spotted up bright and early at 8 the next morning for practice in Queens. Their relationship was made public in June by Maria Sharapova after Williams called her “boring” in an interview.