Mathis Albert became the youngest-ever US goal-scorer and fellow teen Julian Hall netted in back-to-back games as Mauricio Pochettino's side beat Chile 4-2 in a friendly international on Tuesday at St Louis.
Hall created Sebastian Berhalter's opener with a clever dummy, then became the youngest US player to score in his first two appearances before defensive stalwart Chris Richards slammed in a header.
Borussia Dortmund forward Albert – 17 years and four months old – slammed in a fourth in stoppage time, surpassing Christian Pulisic to become the team's youngest-ever goalscorer.
"They're teenagers, but they are mature enough to compete," said Pochettino.
"To play with 16, 17, 18, 19 year-olds, can be good, or can be trendy... but the important thing is, when we call these kids, we are sure that they are going to perform.
"It's only a matter of time."
Diego Ulloa and Maximiliano Gutierrez had briefly put Chile ahead with goals on either side of halftime.
A night that began with an emotional pre-game send-off ceremony to World Cup captain Tim Ream, who confirmed his international retirement, proved to be another full of promise for Pochettino's reinvigorated roster.
YOUNGEST LINEUP
Fresh from thumping Peru 4-1 at the weekend, when 11 players had made their debuts, Pochettino sent out the youngest lineup yet of his two-year tenure, with an average age of 23 years and 25 days.
Gio Reyna was the only player retained from Saturday's win, with Antonee Robinson captaining for the first time.
After scoring on debut, Hall squandered the first decent chance of the game. Played through one-on-one by Berhalter, the 18-year-old rounded Chile's goalkeeper, but blasted his shot wastefully over.
Chile grew dangerous on the break. England-born Chile winger Ben Brereton Diaz lashed the crossbar with a fizzing effort, and Dario Osorio rattled the left post with a curling shot.
But the US struck on their own counter-attack. Sergino Dest rolled a sideways pass across the penalty spot. Hall made a brilliant dummy, letting it through his feet to Berhalter, who slammed it into the bottom-left corner.
In first-half stoppage time, Chile equalized. Another dangerous Osorio corner was parried twice by Brady, his second punch sending the ball back goalward. An almighty goalmouth scramble followed before Ulloa bundled it in.
'FRUSTRATED'
The game had barely resumed when Chile struck again. Gutierrez won an aerial duel on the halfway line, sprinted toward goal, cut inside, and curled a beautiful finish into the bottom corner.
But two minutes later, Hall got his goal, leaping to steer a glancing header from Reyna's lifted cross into the net for 2-2.
Pochettino rang five changes soon after the hour mark, bringing on several more experienced players from the recent World Cup campaign.
Among them was Richards, who quickly slammed home a powerful header from Berhalter's pinpoint outswinging corner.
Deep in stoppage time, Albert's shot rocketed into the crossbar and down across the line – a goal that was confirmed by the referee moments later, and surpassed Pulisic's 2016 goal against Bolivia in the team history books.
Tempers boiled over as both squads and coaching staff flooded onto the pitch for a bout of shoving and shouting before the final whistle.
Richards said the Chileans were "obviously frustrated."
"They're losing the game deservedly, but then if they want to foul our goalie, or they're going to kick him while he's on the ground? I mean, you're on our home soil, so that's not going to fly," he said.