Real Madrid, voted by FIFA as the best European club in the 20th century, completed a three-match sweep in what was termed the World Football Challenge.
After a 4-1 victory over the Los Angeles Galaxy and a 3-0 win over Chivas Guadalajara, Real Madrid finished the trip with another win before 57,305 fans at Lincoln Financial Field, home of the NFL's Philadelphia Eagles.
Michael Farfan spoiled Madrid's bid for a shutout when he scored for the Union in the 80th minute.
Jack McInerney nearly tied the match for the Union in the waning seconds of stoppage time, but backup goalkeeper Jesus Fernandez made a diving save.
There were thousands of fans donning Cristiano Ronaldo jerseys. The former World Player of the Year scored four goals in the first two matches for the Spanish La Liga team, including an impressive hat trick against Chivas Guadalajara last Wednesday in San Diego.
Ronaldo didn't start and entered the match as the second half began.
Callejon scored in the second minute and Ozil followed in the 11th for a 2-0 advantage.
The Union defeated English Premier League side Everton FC 1-0 last Wednesday at their home stadium, PPL Park, in nearby Chester. They had a number of scoring chances, especially in the first half before finally capitalizing late in the match.