On the opening day of the Chennai Open tennis tournament at Chennai today, Japanese sensation Kei Nishikori created a big upset by knocking out the double defending champion and second seed Marin Cilic of Croatia. The world's 98th ranked Nishikori beat his world number 14 rival in three sets 4-6, 7-6, 6-2 in an intense two hour and 33 minutes of scintillating tennis in the first round. With the defeat, Cilic's dream of making a hat-trick of titles at the 398,250 U.S. dollar ATP event came crashing down. The doubles match of between the Indian duo of Somdev Devvarman and Sanam Singh and the combination of R. Haase of Holland and D. Martin of the United States is now in progress.