PARIS - Australian Open winner Serena Williams replaced Angelique Kerber as world No 1 in the latest WTA rankings released on Monday. The American moved up one place courtesy of her victory in Melbourne where she got the better of sister Venus 6-4, 6-4 in the final for a record 23rd Grand Slam title. Kerber’s defence of her Australian Open crown ended with a last 16 loss to Coco Vandeweghe with the German now down to second. Karolina Pliskova climbs two spots to third. WTA rankings: 1. Serena Williams (USA) 7.780 pts, 2. Angelique Kerber (GER) 7.115, 3. Karolina Pliskova (CZE) 5.270, 4. Simona Halep (ROM) 5.073, 5. Dominika Cibulkova (SVK) 4.985, 6. Agnieszka Radwanska (POL) 4.915, 7. Garbine Muguruza (ESP) 4.720, 8. Svetlana Kuznetsova (RUS) 3.915, 10. Johanna Konta (GBR) 3.705.