Tokyo Olympian B Sai Praneeth suffered a shock defeat at the hands of fellow Indian Rithvik Sanjeevi Satish Kumar in the men's singles second round at the Vietnam Open Super 100 badminton tournament on Wednesday. A former World Championships bronze medallist, Praneeth, who has been struggling for form for the last one year, lost 21-17 18-21 13-21 to Satish Kumar to make another early exit from a tournament.