India won the fourth cricket one-day international against Sri Lanka by seven wickets to take an unassailable 3-1 lead in the five-match series at Eden Gardens . Gautam Gambhir notched up his seventh century while Virat Kohli struck his maiden to script India's series-clinching seven-wicket win. Chasing 316 to win, India found themselves in the morass at 23 for two before Gambhir (150 not out) starred in an 224-run stand with Virat Kohli (107) to inject fresh life into the chase and then completed the formality in Dinesh Karthik's (19 not out) company.Earlier, Upul Tharanga (118) hit his seventh ODI century and starred in a 126-run partnership with captain Kumar Sangakkara (60) as Sri Lanka posted 315 for six, the highest score at the venue till India overwhelmed it. Both the teams now move to Delhi for the fifth and final ODI on Sunday.