Ukrainian striker Andriy Shevchenko curled in an 88th-minute freekick as AC Milan rallied to beat Chelsea 3-2 in a Champions World Series match in Philadelphia on Monday.
First half goals from Eidur Gudjohnsen and strike partner Didier Drogba, making his first start for Chelsea, had given Jose Mourinho's English premier league side a 2-1 halftime lead.
However, Alessandro Costacurta equalised for the Italian champions after 76 minutes before Shevchenko's winner consigned Chelsea to their first defeat in three matches on their North American tour.
Brazilian wingback Cafu scored Milan's opening goal in the first half.
The match provided Portuguese defender Ricardo Carvalho with his Chelsea debut.
The Champions World Series features 11 friendly matches at eight venues across the United States and Canada, involving club sides from England, Italy, Scotland, Portugal, Germany and Turkey.
The final match of the tour is on Tuesday when Liverpool take on AS Roma in New Jersey.