RIO DE JANEIRO, March 6 (Reuters) - Flamengo had two players sent off, one for bundling over a ball boy, in a 3-0 defeat away to Nacional in the Libertadores Cup on Thursday.
Martin Palermo scored a club record 181st goal for Argentina's Boca Juniors in their 3-0 home win over Atlas after fellow striker Rodrigo Palacio had scored the first two for the defending champions.
Flamengo, Brazil's most popular club, travelled to Uruguay with four points from two games but appeared unnerved by the raucous atmosphere at the compact Parque Central stadium in Montevideo.
Nacional went ahead in the 41st minute when former Uruguay striker Richard Morales scored from a rebound after goalkeeper Bruno had parried Adrian Romero's long-range shot.
Two minutes later, Flamengo midfielder Toro was off for pushing a ball boy as he ran to collect the ball.
The ball boy, who television reports said was 13 years old, was cheered by the home fans for the rest of the game.
Flamengo were reduced to nine men in the 51st minute when Leo Moura was dismissed for a dangerous tackle on Romero.
Nacional took full advantage as Morales bundled in his second in the 67th minute and Bruno Fornaroli scored with a free kick which sneaked through the Flamengo wall two minutes later.
Nacional went top of Group Four with six points from three games, two ahead of Flamengo, while Peru's Cienciano, who have played a game less, are a further point behind.
In Buenos Aires, Boca were gifted a 33rd-minute opener when Claudio Morel Rodriguez's cross was missed by two Atlas defenders and found Palacio, who coolly slotted the ball home.
The Mexicans often looked threatening but were undone by another mistake in the 81st minute when they lost possession from a throw in on the halfway line.
It took only three touches for Boca to find Palacio, who burst between two defenders to score the second.
Two minutes later, Palermo headed the third to break a club scoring record which had belonged to Francisco Varallo since the 1930s.
The win took Boca top of Group Three with four points from two games, one ahead of Atlas and Chilean champions Colo Colo.