By Rory Carroll

SANTA CLARA, California (Reuters) - The United States might having been hosting Copa America for the first time but a legion of Colombia fans brought a distinct flavor of South America to a sweltering Levi's Stadium for the tournament opener on Friday.

Throngs of yellow-shirted fans partied in the parking lot well before kickoff, belting out salsa music in tribute to the country where the Cali strain of the rhythmic musical style originated.

U.S. fans were there in numbers too, of course.

Decked out in the colors of the "Old Glory" flag and downing beers over smoky barbecues, they chanted "When the Yanks go marching in!" as they approached the stadium in temperatures well above 90 degrees fahrenheit (32 Celsius).

Although many of the Colombia fans had traveled up from their homeland, some, like Santiago Velez, were born in the U.S.

Sporting the yellow jersey of Los Cafetero, Velez was in the parking lot demonstrating the "Soccer Sidekick".

Velez feels strongly about how young soccer players are developed and hopes the training tool, which is made by a company he manages, will help bring on a more skilful generation of players.

The 23-year-old said he could not support Team USA until the country improved its approach to training young players, putting less emphasis on winning and more on the fundamentals of the game.

"I'll start rooting for the U.S. when we start playing the right way and developing players," he said before the Colombians showcased their skills in a 2-0 victory.

Miguel Padilla, 32, from San Jose, said he was happy to see the United States hosting the tournament and the U.S. men's team in it for the first time since 2007.

Despite the heat, he wore a pillowy red, white and blue Captain America costume complete with a shield and joked he had prepared for Friday by hitting the sauna in it.

"It's a little sacrifice for our country," he said.

(Additional reporting by Noel Randewich, editing by Nick Mulvenney)