The English giants are among several Premiership sides currently touring Asia, in what are widely seen as attempts to build up their fanbases in a potentially hugely lucrative market.
But despite a large crowd of 42,000 on Wednesday night, including many casual fans apparently backing both sides, few blue-shirted Shenhua supporters were to be seen in the stadium except a knot of 100 or so behind one goal.
Earlier in the day, an online campaign started by Shenhua fans had urged the club's supporters to shun the event.
A post from one fan widely circulated on China's Twitter-like weibos read: "If you are a real Shenhua supporter, cancel any plan you have to attend this game against Manchester United.
"Let the sponsors see that this game, which reeks of business and money, should not be scheduled in the middle of our league season."
Also popular were a series of photographs of fans of Beijing Guoan and Shanghai Shenhua -- traditionally fierce rivals -- who put aside their differences to make a joint statement against mid-season exhibition matches.
Supporters of the two clubs were pictured standing next to a Manchester United merchandising booth with a large banner in English reading: "Love football, hate business".
"I don't think Man United would agree to play Shenhua in the middle of the English Premier League season -- so neither should we," Shenhua fan Ma Haiping told AFP. "I think this is a game about business, I think it's totally boring."
Shanghai Shenhua rested almost all their key players for the friendly, including blockbuster signings Nicolas Anelka and Didier Drogba.
Other supporters said high ticket prices had deterred them from attending -- the cheapest seats were selling for 180 yuan ($28) each, nearly a quarter of the price of a Shenhua season ticket.