India captain Mahendra Singh Dhoni won the toss and decided to bat first in the opening one-day international against Sri Lanka at Mahinda Rajapaksa Stadium on Saturday.It is Indias first 50-over match in four months, a stretch that also includes seven weeks off, and must find its form quickly as it starts a five-match series.This is also Indias first match at Hambantota.Sri Lanka goes into the match confident after recently beating Pakistan in a one-day and test series.