The winger, a late addition to the El Tri roster due to an injury to another call-up, started Mexico's Group A opener against Cuba on Saturday at the Rose Bowl in Pasadena, Calif. And he opened his goals account at senior level just two minutes in, cleaning up a rebound off the post.
He added his second goal just before halftime to make it 4-0 for Mexico.
After setting up Alexis Vega's first career Mexico goal, Antuna then completed the hat trick in the 80th minute, to bring the score to 7-0, the final margin of victory.
The 21-year-old is on loan this season at the Galaxy from Manchester City. Starting each of LA's MLS regular season games so far this season, he has two goals and two assists in 16 games to date in his MLS career.