Washington, Aug 5 - India's Somdev Devvarman stunned World No.15 and sixth seed Marin Cilic of Croatia in straight sets 7-5, 6-4 to advance to the third round of the Legg Mason Tennis Classic here Wednesday.

Somdev, who lost to Cilic in the final of the ATP Chennai Open in January, avenged the defeat in great style. It was his first victory against a top-20 player.

Somdev, 24, served brilliantly and battled to save five of the seven break points.

The Indian, ranked 153rd in the latest ATP rankings, said after the one hour 42 minutes match that it was his greatest career victory.

'All along I played well,' Somdev said.

'My game plan was to compete as hard as possible. I took my chances well. I'm proud of the result.'

Somdev, a two-time US college national champion at nearby University of Virginia, got good vocal support from the familiar local crowd.