Luis Suarez struck twice in three minutes as Uruguay beat Peru 2-0 in an enthralling encounter on Tuesday to reach the Copa America final and remain on course for a record 15th title.
Uruguay, fourth at last year's World Cup, go into the final at the Monumental in Buenos Aires against either Paraguay or Venezuela who clash in Wednesday's semi-final in Mendoza.
Uruguay went ahead eight minutes into the second half when Diego Forlan, the 2010 World Cup's best player, shot left-footed from outside the box forcing Raul Fernandez into a diving save and the ever alert Suarez nipped in to net the rebound from a tight angle on the right.
Suarez scored again three minutes later when Alvaro Pereira passed between two defenders from the left and the striker beat the offside trap, rounded Fernandez on the edge of the box and steered the ball gently home.
Peru captain Juan Vargas was then sent off in the 69th minute for elbowing Uruguay defender Sebastian Coates in the face.
"Today was a match in which we had to go out and attack, to play, and luckily it worked out well," Suarez, comparing it with a more defensive performance against hosts Argentina in Uruguay's quarter-final win on penalties, said in a televised interview.
"I think that to play the final in Argentina is great. Now we have to enjoy (the moment), the important thing is we reached the final which was our objective."
The first clear chance fell to Uruguayan midfielder Pereira in the 16th minute from a throw-in on the right but his shot from point-blank range was smothered by Fernandez.
Eight minutes later Peru had a chance when Vargas sent a low ball in from the left touchline across the face of goal but forwards Paolo Guerrero and Luis Advincula could not get a touch.
Peru central defender Wilmer Acasiete then had to be alert to cut across from the left to make a last-ditch clearance from Suarez in the 35th minute as Uruguay pushed for the opener.
Uruguay thought they had taken the lead when they had the ball in the net from a Forlan freekick in the 42nd but Pereira's effort was ruled offside.
In the second half, despite falling two behind and being a man down, Peru continued to press and defender Walter Vilchez had a header from a corner saved on the line by Fernando Muslera in the 73rd minute.
Guerrero then struck a swerving shot that deceived the Uruguay goalkeeper, who could only palm the ball before goalwards before diving to prevent it going over his line.
At the death, Guerrero did not quite get his head to substitute William Chiroque's right cross as another Peru chance went begging.