The 18-year-old German-American earned his first cap with the national team in a back-and-forth match that saw the U.S. blow a two-goal lead.
But that would be the only highlight of the second half for the U.S.
The Tampa native entered in the 58th with his new squad up one goal, but the U.S. was unable to hold the lead as it played to 2-2 draw with Mexico in an international friendly at the University of Phoenix Stadium.
Michael Bradley and Chris Wondolowski scored for the Stars and Stripes in the first half before Mexico stole the momentum in the final 45 minutes.
Rafa Marquez put in a beautiful header minutes after halftime and Alan Pulido tapped in a rebound in the 67th minute to secure a tie in the battle between CONCACAF neighbors.
In perhaps the last chance for several fringe players to make their case for a spot on the World Cup roster, Green started on the bench. He is viewed as one of the biggest prospects in U.S. soccer history.
Green officially joins fellow German-Americans Terrence Boyd, Timmy Chandler, Fabian Johnson, Jermaine Jones, Alfredo Morales, John Anthony Brooks and Daniel Williams in the U.S. player pool.
Landon Donovan, a lock for the World Cup, also came on late as a reserve. The LA Galaxy midfielder's fitness had failed to impress Klinsmann in practices leading to the game.
Many had hoped to see Donovan start alongside stars Clint Dempsey and Bradley. The trio haven't started together in a national team game since June 12, 2012.
But Donovan's presence wasn't needed early on, as Bradley stole the show.
It took less than 15 minutes for the U.S. to find the goal after Graham Zusi delivered a corner kick to the far post and Bradley raced down the right side of the box to tap it in.
It was the 12th international goal in 83 caps for the Toronto FC midfielder.
The Americans made it 2-0 thanks to Wondolowski being at the right place at the right time. Following solid midfield play, Bradley headed the ball across the net to assist the 27th-minute strike.
The second half didn't start out as well for the Americans, however. Off a corner, Marquez came off a pick and headed home his 15th goal for El Tri past goalkeeper Nick Rimando in the 49th minute.
Despite the momentum shift, Klinsmann still decided to give Green a run. The 18-year-old from Bayern Munich's developmental system came on with Donovan and Clarence Goodson.
The substitutions didn't help for the home side.
El Tri continued to pressure the U.S. throughout the second half, and Pulido tied the game at two apiece as he put in a rebound after Paul Aguilar hit the left post.
The U.S. had looked to have scored the winner in the 85 minute, but Eddie Johnson was arguably called offsides after slipping behind Mexico's defense and putting the ball in the net.
Moments later, it appeared Green had drawn a penalty when he was taken down on the line of the box, but the referee decided not to blow his whistle.
Green, who played for both German and U.S. teams in the U-16 to U-19 levels, declined an invite from Klinsmann last year. He was part of the USA's camp in Frankfurt ahead of last month's Ukraine match, but didn't travel with the team to Cyprus.