India defeated Sri Lanka by 20 runs in the fifth and final cricket One-day international to clinch the series 4-1 at Pallekele International Stadium here today.The batsmen who contributed importantly to India's total of 294 were, Gautam Gambhir 88, Manoj Tiwary 65 and M S Dhoni 58.For Srilanka, Lasith Malinga took 3 wickets for 64 runs and Nuwan Pradeep got 2 wickets for 63 runs. Earlier, India won the toss and skipper M S Dhoni elected to bat first.