The winger came on at the same time in the second half as Palmeiras coach Abel Ferreira withdrew teenage sensation Estevao Willian, a move that appeared baffling at the time but ultimately proved inspired.
The tie had reached the 100th minute when Paulinho collected a pass by Richard Rios on the right flank and was afforded the time and space to come inside into the box before slotting a low shot into the far corner.
That sparked wild celebrations among the Palmeiras fans who made up the vast majority of the 33,657 crowd inside Lincoln Financial Field, and the side from Sao Paulo held on to win the last-16 showdown despite having captain Gustavo Gomez sent off late on.
“I am really happy. Luckily I managed to get the goal,” the former Bayer Leverkusen player, who has struggled with injury since signing for Palmeiras at the start of the year, told broadcaster DAZN.
“The coach is doing all he can to help me settle into the squad in this difficult time for me, because I had a serious injury which still causes me pain.
“There is no time to feel sorry for yourself in this competition. You have to make things happen and that is what I am doing.”
Winners of the Copa Libertadores in 2020 and 2021, Palmeiras will now stay in Philadelphia for a last-eight tie next Friday against either Benfica or Chelsea, who meet later Saturday in Charlotte.
They had been the more dangerous side throughout in this meeting of the top two in last year’s Brazilian league, with almost all of the chances falling the way of the men in green.
Rio de Janeiro side Botafogo pipped Palmeiras to the domestic title and also won the Copa Libertadores for the first time in their history in 2024.
They then lost their coach and several key players, but still managed to beat European champions Paris Saint-Germain during the group stage of the Club World Cup as they qualified for the knockout phase ahead of Atletico Madrid.
Nevertheless Palmeiras were the more lively of the two teams in a game played in warm midday conditions in Philadelphia.
All eyes were on Estevao, the 18-year-old winger who will join Chelsea once the tournament is over and is seen as Brazil’s next big thing.
He found it hard to make an impact in what was for long spells a disappointing game pockmarked by moments of quality.
Colombian midfielder Rios came close to scoring in first-half stoppage time with a thunderous shot from the edge of the box that was deflected onto the roof of the net.
Estevao then came to life after the restart, forcing a good save from Botafogo goalkeeper John Victor and then putting the ball in the net only to be denied by an offside flag.
There was surprise around the stadium when the starlet was taken off just after the hour alongside striker Vitor Roque, with Luighi and Paulinho sent into the attack.
A Mauricio header from a Joaquin Piquerez cross was tipped over and Paulinho then blazed high from a good position as normal time ended goalless.
Into the extra half-hour they went. A Rios pile-driver was parried behind before the goal finally arrived thanks to the once-capped Brazil winger who played in the Atletico Mineiro side beaten by Botafogo in last year’s Libertadores final.
The substitute was then promptly substituted, his job done for the day.
Botafogo pushed for an equaliser that would have led to penalties, but could not find it even after Paraguayan centre-back Gomez walked for a second booking in the 116th minute for grappling off the ball with Alexander Barboza. (AFP)