The visitors got off to an ideal start at the Hongkou Stadium when Alessandro Diamanti scored his first goal since March after nine minutes.
On a day when Guangzhou were reported to have completed a deal for Alberto Gilardino - it was another Italian who stole the show early on with an expert free-kick.
However, struggling Shenhua, without a league win since May, drew level before the break when Di Gao equalised after 27 minutes.
Marcello Lippi opted to bring on Hanchao Yu and Xuri Zhao short of the hour, but initially it failed to inspire a second, with Rong's introduction proving key.
With 91 minutes on the clock, Fang Mei crossed for the China international to make himself a hero.
His second goal of the campaign was enough to see off the hosts and extend Guangzhou's lead at the top of the Chinese Super League to four points.
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