Australia's Ash Barty has reclaimed the number one spot in the WTA rankings less than a month after losing it while U.S. Open champion Bianca Andreescu moved up to a career-high fifth after her maiden Grand Slam win in New York. Andreescu beat Serena Williams 6-3 7-5 in Saturday's final to maintain a 13-match unbeaten run, where she also won the Canadian Open, to break into