Gabriel Barbosa scored twice in a dramatic final five minutes as Flamengo came from a goal down to beat River Plate and win their first Copa Libertadores title since 1981.
The Brazilian giants were second best for much of the match after Rafael Santos Borre swept home from Matias Suarez's pull-back in the 14th minute to the delight of the River fans inside the 80,000-capacity Estadio Monumental in Lima.
The 24-year-old Colombian was then inches away from making it 2-0 with a sweet strike from 25 yards out.
Flamengo's best chances of an equaliser came in the space of a few seconds when Barbosa had a shot blocked and Everton Ribeiro's follow up was well held by keeper Franco Armani.
But then came the late fightback that turned the final on its head.
First, Barbosa timed his run to perfection to turn in Bruno Henrique's square ball, then the striker on loan from Inter Milan outmuscled the defence in the penalty box to slot in a 92nd-minute winner.
There was still time for two red cards in the final few seconds, with Exequiel Palacios sent off for kicking Henrique while he was on the ground before Flamengo's two-goal hero was sent off for sarcastic applause.
The final of South America's biggest club football competition, which started life in 1960, was moved from Santiago to the Peruvian city because of social unrest in Chile's capital.
This was the first time since 1988 that the tournament has been decided in a one-off game.
Supporters from both sides occupied Lima's streets in their thousands before the match, with reports stating some River fans travelled the 2,500 miles from Buenos Aires to Peru by buses provided by the club.
Flamengo have now qualified for the 2019 Fifa Club World Cup in Qatar and could face European champions Liverpool if they both reach the final on 21 December.