Marcello Lippi's men - who have tasted defeat just once in the Chinese Super League and are on the verge of winning the title for a third season in a row - headed into the second leg of the quarter-final clash holding a 2-0 aggregate lead.
Lekhwiya's hopes of progression appeared slim, and they were always second best in what proved to be an extremely one-sided contest.
It took the visitors just 15 minutes to break the deadlock, midfielder Dario Conca finding the net as he turned in a right-wing free-kick at the near post.
Guangzhou's lead was doubled only a minute later, Elkeson's curling free-kick bouncing in off the post, leaving home goalkeeper Amine Lecomte-Addani helpless.
By that point the tie was all but over, but Guangzhou continued to be ruthless in front of goal, and Lippi's side duly added a third just after the half-hour mark, Brazilian forward Muriqui slotting home with a smart finish.
The hosts refused to lie down, though, and they did restore some respectability six minutes into the second half as midfielder Nam Tae-Hee reduced the deficit.
But it was Guangzhou who were in command throughout, and they rounded off a comfortable win 13 minutes from time as Elkeson scored his second.
The first leg of the semi-finals are to take place on September 24, with Lippi's men set to face either Kashiwa Reysol or Al Shabab.
