The 27-year-old's second-half effort helped Roger Schmidt's men extend their unbeaten run to eight games in the Chinese top-flight.
Elkeson broke the deadlock at the Shanghai Stadium to put the hosts ahead in the 25th minute.
Just after the break, Piao Cheng drew the Beijing outfit levelled before Bakambu sealed the maximum points in the 52nd minute.
The former Villarreal and Bursaspor forward has found the back of the net in five of his last six games for the Imperial Guards.
Beijing Guoan moved to the third spot in the table with 18 points from nine games. They host Guangzhou R&F next on May 11.