United States coach Jurgen Klinsmann insists his side are not scared of Lionel Messi and Co. as they prepare to face Argentina in the Copa America Centenario semi-finals. 

Hosts USA qualified for the last-four of the tournament for just the second time courtesy of a hard-fought 2-1 win over Ecuador last Thursday, while Argentina dispatched Venezuela 4-1.

Klinsmann's men have been in good form since their defeat to Colombia in the Copa opener, scoring seven goals and conceded just one in their three next games. 

But while they must face the world's number one ranked side for a spot in the final, Klinsmann insists his players will not be overawed by the occasion.

"We are not scared of them at all," the 51-year-old said on Sunday. "We admire their players. This is now a special moment. 

"I told the players yesterday before we started training, 'This is a once-in-a-lifetime opportunity now. You got into the semi-final, you made yourself proud but now go for more.'"

"We are ready to bite, to fight, to chase them, to be all over them. If we repeat that and add a couple more percent to it, it's going to be fun.

"We have to be on top of our game defensively – that's a no-brainer – but we've done extremely well in the whole competition defensively."