Pathan scored an unbeaten 29 and shared a valuable 77-run stand with skipper Mahendra Singh Dhoni in India's score of 274 for nine.
Pathan then scalped five wickets to help India beat Sri Lanka by 20 runs.
"God's grace. I was bowling well throughout the series. Had too many bad deliveries today but got five wickets. The batting gave me a lot of confidence, it came at the right time," Pathan said after being adjudged Man-of-the-match.
Pathan said the conditions too suited his style of bowling.
"In Premadasa and here, the ball does swing with the humid conditions, and with the two new balls it does help swing the ball. It's a great feeling," he said.
Young Indian batsman Virat Kohli, who slammed two centuries in the series, was declared Man of the Series.
Angelo Mathews, who led Sri Lanka as regular skipper Mahela Jaywardene was rested, acknowledged the gritty batting by Lahiru Thirimanne (77) and Jeevan Mendis (72).
"Encouraging to see Thirimanne and Mendis taking on the challenge. Unfortunately we fell short by 20 runs, we gave away some runs on the field. The Indians have a very good batting line-up. But we did too many mistakes on specific days and that was the result of our downfall. Mendis works really hard and is a wonderful asset for us," Mathews said. More