Federico Macheda scored two early goals, Mexican star Hernandez struck on his debut and United won 5-2 on Wednesday night in the final exhibition game of its North American tour.
Darron Gibson and Tom Cleverley added goals for the Red Devils, tuning up for the start of the Premier League season next month.
Houston Dynamo star Brian Ching had a goal and an assist for the All-Stars.
The sellout crowd was announced at 70,728, the largest for an MLS All-Star game since the first one in 1996 drew 78,416 to Giants Stadium. The attendance figure was the largest for a soccer game at Reliant Stadium.