World champion Vishwanathan Anand defeated former FIDE world champion Ruslan Ponomariov of the Ukraine in his opening round in group 'A' competition of the 73rd Tata Steel chess tournament in The Netherlands.The win was an important boost for Anand to regain the top spot in rating list, which he lost to Norway's Magnus Carlsen earlier this month. While, International Master Tania Sachdev caused a major upset in the 'C' group being held simultaneously defeating second seed Ivan Ivanisevic of Serbia. Tania emerged as early leader in her group while in the 'B' group, the lone Indian Surya Shekhar Ganguly went down to Gabriel Sargissian of Armenia.