PALLEKELE, Sri Lanka, Aug 12 (Reuters) India openers KL Rahul and Shikhar Dhawan punished Sri Lanka's bowling attack with brisk half centuries today, laying the foundation for a big first innings total in the third and final test. After winning the toss and opting to bat, India captain Virat Kohli could not have asked for a better start as his side began their bid to complete a series whitewash over the hosts. Rahul was on 67 and Dhawan 64 as India reached 134 without loss at lunch on the opening day. Following wins inside four days in Galle and Colombo, the world's top-ranked side have an unassailable 2-0 lead and the injury-hit hosts face another stiff task against Kohli's men in the finale. On an easy surface for batting, the Indian openers picked up boundaries at will and also made Sri Lanka pay for their profligacy. Dhawan was given a reprieve when he was on one, as his edge went through the slip cordon off left-arm seamer Vishwa Fernando. Lahiru Kumara could not hold on to a mishit from Rahul when he was on 28, spilling the chance off Dimuth Karunaratne. Both batsmen made the most of the opportunities with Dhawan reaching his fourth test fifty off just 45 deliveries while right-handed Rahul brought up his seventh consecutive score of 50 or more in 67 deliveries. Left-arm wrist spinner Kuldeep Yadav was the only change for the touring side, called up as a replacement for suspended left-arm spinner Ravindra Jadeja. The hosts have been hurt by injuries throughout the series and will be missing both spin spearhead Rangana Herath and paceman Nuwan Pradeep. Middle-order batsman Dhananjaya de Silva was dropped after scores of nought and 17 in Colombo. Sri Lanka brought in left-arm wrist-spinner Lakshan Sandakan, along with pace duo Kumara and Fernando. REUTERS AKC 1222