Chile matched Brazil for most of a bad-tempered match but Ribeiro fired home after 64 minutes to give the visitors all three points.
Brazil have won all seven of their qualifiers so far and the five-times world champions are six points clear of Argentina, who beat Venezuela earlier in the night, in the 10-team South American group.
Brazil’s preparations for the match were thrown into turmoil by some clubs’ decision not to release their players due to concerns over the lengthy quarantine on their return.
And while Brazil could still count on the likes of Neymar, Casemiro and Marquinhos they were second best for most of the first half and had goalkeeper Weverton to thank for a series of saves that kept the game goalless.
Coach Tite introduced Ribeiro and Gerson for Vinicius Junior and Bruno Guimaraes at halftime and Ribeiro justified his inclusion when he seized on a parried Neymar shot to fire home in a packed penalty box.
The top four qualify automatically for Qatar and the fifth-placed side goes into an inter-regional playoff.