With 23 minutes gone in the second period, Paulinho found himself unmarked at a corner and he had enough time to bring the ball down and hammer it into the roof of the net from eight metres out.
Coutinho, who had replaced Renato Augusto a few moments earlier, grabbed a fine second after 75 minutes when he darted forward and exchanged passes with Gabriel Jesus before firing home from close range.
The result means that Brazil, who became the first South American side to qualify for Russia earlier this year, sit atop the group with 36 points after 15 games, 11 points clear of second-placed Colombia.
"It was another important result, the run we’re on is very good," winger Willian said after the game. "The first half was difficult, we couldn’t find space but in the second half we got the ball moving faster and found the way to goal."
The win was coach Tite's ninth consecutive victory in competitive matches since he took over as coach in June last year. His revamped side have scored 26 goals and conceded only two in the process.
Opponents Ecuador, meanwhile, have stumbled badly after winning all four of their opening qualifiers. The Andean side have picked up maximum points in only two of the 11 since, and tonight’s result means they fall to seventh place in the South American qualifying table.
The top four teams qualify automatically for Russia 2018 and the fifth-placed side goes into a play-off against a rival from the Oceania confederation.
Brazil have never lost a World Cup qualifier at home and they never looked in danger against their limited rivals.
Neymar produced some flashes of individual brilliance but was not as influential as in the past, and it was the introduction of Coutinho 13 minutes into the second half that turned the game in favour of the home side.
(Editing by Ian Ransom)
