The three-time defending champions of China were knocked out of the quarter-finals of Asia's premier club competition by Western Sydney Wanderers on Wednesday.
That was despite winning the second leg 2-1, with Guangzhou's away goals defeat ending their chance of retaining their crown.
But Marcello Lippi's side quickly responded on their return to league action as four second-half goals helped them to a thumping home win.
Elkeson – top scorer in the CSL last term – was Guangzhou's star man, scoring a hat-trick.
Rene Junior and Alberto Gilardino then scored before Elkeson wrapped up the rout with seven minutes left, with his 20th league goal of the season.
The defeat keeps Liaoning Whowin in the CSL's relegation zone, four points above rock-bottom Harbin Yiteng.
The title race appears to be a two-team race after Shanghai SIPG, who sit third, fell to 10 points behind the leaders with seven matches remaining.
Ryan McGowan's own goal cancelled out Liu Binbin's opener, but Dai Lin struck a 62nd-minute winner for Shandong.
