MEXICO CITY (Reuters) - An American wrestler working in Mexico is tapping into anger at Donald Trump, whipping crowds into a frenzy with an act as a supporter of the locally loathed U.S. president.

Sam Polinsky, known as Sam Adonis, climbs into the ring of Mexico City's main wresting stadium waving an American flag that has Trump's face emblazoned over the red, white and blue.

"I hear it all, and the Mexican fans are screaming the worst expletives they can at me. They are throwing beers at me, they are throwing popcorn at me," Polinsky said.

The anger is all in the fun of the sport of "lucha libre," which pits rule-breaking bad guys, or "rudos," against noble "tecnicos," he said. After the match, fans line up to get photos with the blond wrestler and have him sign autographs for their kids.

"Fans in Mexican lucha libre are some of the best on earth. Two thousand people in Mexico can make more noise than 20,000 people in the United States," Polinsky said.

Lucha libre, Spanish for "free fighting," is a form of wrestling that is often considered Mexico's second most popular sport, trailing only soccer.

Polinsky previously worked in Europe and the United States, but he took his career to a new level after he moved to Mexico last April just as Trump was rising in the Republican primaries.

He tweaked his initial act as a ladies man by adding his Trump flag and recasting himself as a typical U.S. Trump supporter.

"I can't say I support Trump but I definitely respect Trump," he said. "He is just himself, and if you like it, you like it, and if you don't, you don't."

Three weeks into his administration, Trump has vowed to move ahead with construction of a wall on the U.S.-Mexico border, repeatedly insisting that Mexico would pay for it, while also saying he will deport millions of unauthorized immigrants.

Mexican President Enrique Pena Nieto has repeatedly said that Mexico will not pay for a border wall, and he canceled a visit to the United States over the issue.

Thousands of protesters in more than a dozen Mexican cities took to the streets on Sunday to express their opposition to Trump and criticize Pena Nieto as a weak leader who has presided over rampant corruption and violence at home.

(Reporting by Reuters Video News; Writing by Michael O'Boyle)