First-half goals from Goran Pandev and Samuel Eto'o and a late strike by substitute Jonathan Biabiany gave the Italian team their third world title after they won the former Intercontinental Cup in 1964 and 1965.
Inter were 13 points off the pace in Serie A before the weekend's matches. It was the fourth time in a row a European team has won the tournament -- although UEFA's representatives had eight South Americans and one African in their starting line-up.
Mazembe, from Democratic Republic of Congo, were the first team from outside Europe and South America to reach the final since the tournament was started in its current format in 2005.
"We are a true team," Pandev told reporters. "When it counts we don't make a mistake.”
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