Chile took another step towards their dream of winning a first Copa America on home soil with a 2-1 win over Peru but Eduardo Vargas' match-winning double was overshadowed by an early refereeing decision that turned the game the hosts' way.
Carlos Zambrano's harsh sending off for a high tackle after 20 minutes was the second game in a row that Chile's rivals have been hit with controversial red cards.
The decision was a hard one to swallow for Peru, who in spite of being underdogs had started well in front of a capacity crowd at Santiago's National Stadium.
Peru refused to cave in after Zambrano's dismissal and matched their hosts in a pulsating first half.
It looked like the teams would go in all square at half time but Chile took the lead when striker Vargas poked the ball home from three yards after an Alexis Sanchez cross had come back off the post.
Peru came back into the game and equalised on the hour mark but their lead lasted just four minutes, however, and again it was Vargas who did the damage as he picked up the ball in midfield and lashed home an unstoppable strike from 30 yards.
Chile's opponents in last week's quarter-final, Uruguay, were reduced to nine men in controversial fashion with Edinson Cavani and Jorge Fucile being sent off in Santiago.
Cavani's red card came after Chile defender Gonzalo Jara stuck his finger up the striker's backside and when he responded with the slightest of touches Jara fell to the ground theatrically, prompting the referee to send the Uruguayan off.
Chile, who have never won the Copa America in its 99-year existence, will play the winners of Tuesday's semi-final between Argentina and Paraguay.
Source: Al Jazeera and agencies