The 102-ranked Indian won 6-2 6-3 against his Australian rival, placed 64 in the ATP charts, in one hour and 13 minutes in the euro 485,760 clay court event. (Agencies)
The win is Somdev's first after suffering five straight first-round defeats in the last three months. The last time he won a singles match on the ATP tour was when he defeated Juan Martin del Potro in ATP 500 Dubai event in February.
He next faces top seed and world number six Tomas Berdych from Czech Republic.
Somdev broke Ebden early to take a 2-1 lead and raced away with the opening set. The second set was fought tightly as the two players were locked 3-3, but Somdev broke the Australian in the seventh game and one more time in the ninth to eke out a confidence-boosting win.
A struggling Somdev Devvarman was dropped out of top-100 bracket in the singles rankings as the Indian slipped to 102 with the loss of two places.
Somdev has been struggling since winning the Delhi Open challenger title and failed to cross the first round hurdle in five consecutive tournaments on the ATP tour.
Also sliding in the ATP ranking ladder was India's second best singles player, Yuki Bhambri, who lost four spots to be 153. The tall and big serving Saketh Myneni though jumped seven places to be 262.
In the doubles, Leander Paes continued to be India's best ranked player and the only one in top-10 at number nine. Davis Cupper Rohan Bopanna was next best at number 14.
Mahesh Bhupathi, who will retire this year and will be playing only select events, gained a place to be 46.
Left-handed Delhi boy Divij Sharan suffered a loss of four places to take the 71st spot this week. In the WTA rankings, Sania Mirza maintained her eighth rank in the doubles chart.
The 102-ranked Indian won 6-2 6-3 against his Australian rival, placed 64 in the ATP charts, in one hour and 13 minutes in the euro 485,760 clay court event.