Paolo Guerrero scored the only goal when he reacted quickest to head past three Blues players from five yards.
Fernando Torres had a chance to force extra time but fired straight at Cassio with only the goalkeeper to beat.
Chelsea's Gary Cahill, who also missed a good opportunity, was sent off after clashing with Emerson late in the game.
Torres had the ball in the net in injury-time when he headed home but his effort was ruled out as Corinthians held on to win the trophy.
It may prove to be a double whammy for the Blues. Both Manchester United and Manchester City won over the weekend and forged further ahead of Chelsea in the Premier League title race. They are fully 13 points behind leaders Manchester United and whilst remaining 3rd may only retain that on goal difference if Spurs beat swansea on sunday afternoon. On top of an exhausting trip, Chelsea now need to find a fixture date for the game they have missed this weekend against Southampton.
Manchester United remain the only English side to have won the competition.
Club World Cup: Past winners
•2000 - Corinthians (Brazil)
•2005 - Sao Paulo (Brazil)
•2006 - Internacional (Brazil)
•2007 - AC Milan
•2008 - Manchester United
•2009 - Barcelona
•2010 - Inter Milan
•2011 - Barcelona