Another benchmark for the United States. Another huge goal for Clint Dempsey.

As unlikely as it seemed a few weeks ago, the U.S. is in the semifinals of the Copa America.

Dempsey scored for the third straight game and set up Gyasi Zardes for a tap-in goal, boosting the United States into the Copa America semifinals with a wild 2-1 win over Ecuador on Thursday night.

Playing before a boisterous and almost completely partisan home crowd of 47,322 in the soccer-mad Pacific Northwest, the U.S. won a knockout game against a nation outside its region for only the second time and will play Argentina or Venezuela on Tuesday in Houston.

And the Americans did it on the back of Dempsey, their fiery 33-year-old striker whose place on the U.S. team was debated early this year. Dempsey's 52nd international goal, five behind Landon Donovan's American record, put the U.S. ahead in the 22nd minute. Zardes guided Dempsey's cross into the net in the 65th for his sixth goal and a 2-0 lead.

Michael Arroyo scored for Ecuador in the 74th minute, making for a tense ending, and Enner Valencia missed a pair of great chances moments later on a pair of headers.

It was a chippy game that became costly for the U.S. American midfielder Jermaine Jones was shown a red card during a 52nd-minute confrontation that also saw Ecuador winger Antonio Valencia sent off after a second yellow card for a harsh tackle on Alejandro Bedoya along the sideline .

U.S. players immediately rushed in to the scrum after Valencia's tackle, and Jones raised an arm at Arroyo. Colombian referee Wilmar Roldan immediately showed a red card to Jones.

Jones will be suspended for the semifinal along with Bedoya and Bobby Wood, who both got their second yellow cards of the tournament.

Ecuador coach Gustavo Quinteros also appeared to be sent off late in the match.

The only previous knockout win for the U.S. over a non-CONCACAF team was against Spain in the 2009 Confederations Cup semifinal. The only other U.S. appearance in the Copa semifinals was in 1995, when it advanced to the final four by beating Mexico, then was eliminated by Brazil.

The Americans are now assured two more games in the tournament: the semifinal and either a third-place match or the final. The Argentina-Venezuela game is Saturday night, so the U.S. will have two extra days of rest.