Anna Wintour will be squaring off with former French Vogue editor Carine Roitfeld when Roitfeld launches her new magazine, CR Fashion Book, on Sept. 13. The fashion world’s bracing for a battle, reveals Page Six Magazine — with one insider even claiming the top editrixes can’t be seated near, or across from, one another during Fashion Week. “Anna’s not worried,” says stylist Phillip Bloch. “It’s more like, ‘Ugh, that pest is here. Guess I’m not getting rid of her anytime soon.’ ” Jerry Oppenheimer, who penned a book on Wintour, agrees. “Anna is an institution, and Carine, who seems to be going through some sort of a career midlife crisis, is never going to usurp Anna’s immense political power and editorial clout,” he says. On Team Roitfeld is Dennis Freedman, creative director for Barneys. “There is so much room for a breath of fresh air, and a breath of fresh air that is not afraid to make some mistakes,” he says. Don’t miss Page Six Magazine, free in the New York Post tomorrow.