India's Viswanathan Anand has regained the sole lead with a sparkling victory over former challenger Veselin Topalov from Bulgaria in the ninth round of the Candidates Chess tournament in Khanty Mansiysk, Russia.The hard-earned victory proved crucial for five-time World Champion Anand as he took his tally to six points out of a possible nine. With five rounds still to come, Anand now enjoys a full point lead over Aronian, who remains on five points