Serena Williams of the United States has won her fourth Women's Singles US Open title in New York. In the final match played a short while ago, fourth seeded Serena showed incredible resolve as she beat the top seeded Victoria Azarenka of Belarus, 2-6, 6-2, 7-5 in two hours and 18 minutes. Besides the fourth US Open title, this was Serena's 15th Grand Slam singles crown.In the Men's Singles, Serbia's Novak Djokovic has stormed into the finals. In the semi-finals yesterday, second seeded Djokovic beat David Ferrer of Spain 2-6, 6-1, 6-4, 6-2. In the finals today, Djokovic will meet Briton Andy Murray, who had defeated Tomas Berdych of the Czech Republic 5-7, 6-2, 6-1, 7-6 in the other semi-final earlier.Meanwhile, the Italian duo of Sara Errani and Roberta Vinci has won the Women's Doubles trophy. In the title clash, the second seeded Italian duo defeated the Czech pair of Andrea Hlavackova and Lucie Hradecka, 6-4, 6-2 to win the title.