Fedrico Macheda scored midway through the first half as United managed to clinch a marginal 1-0 victory over South Africa's mid-table club AmaZulu.
Red Devils boss Sir Alex Ferguson opted for reserve players along with veterans Rio Ferdinand, Paul Scholes while want-away striker Dimitar Berbatov started in a much deeper role behind Javier Hernandez and Macheda. Berbatov's sublime through pass to Macheda ended being the winning goal.
The Bulgarian was United's most impressive player with two brilliant shots saved by the hosts goalkeeper while one attempt was cleared off the line.
New signing Japan star Shinji Kagawa came off the bench with only two minutes remaining.
Roberto di Matteo's Chelsea began their pre-season tour of the United States with a 4-2 win over the Seattle Sounders.
Belgian star Romelu Lukaku scored twice in the first half while new signings Eden Hazard and Marko Marin found the net in their first game for the Blues.
Lukaku, who was ignored for most of the last season, impressed this time around after opening the scoring in the third minute, thanks to Josh McEachran's pass, and netted another two minutes before half-time.
Fredy Montero's brace got the hosts back on track after Hazard's deflected strike in the 10th minute gave the European Champions a narrow lead.
However, Marin's fine strike put the Blues in front in the 39th minute and Lukaku wrapped an exciting first half with the fourth and final goal four minutes later.
Meanwhile, Tottenham beat Stevenage 2-0 as debutant Gylfi Sigurdsson opened the scoring while youngster Yago Falque scored later on to clinch a deserved victory under new boss Andre Villas-Boas.