Christian Pulisic fired the United States into the last 16 of the World Cup on Tuesday as the Americans downed Iran 1-0 in their winners-take-all match.
Chelsea star Pulisic bundled home the game's only goal on 38 minutes to set up a second-round clash with Group A winners the Netherlands later.
"The guys grinded, gave every single ounce and we are undefeated going into the next round," U.S. coach Gregg Berhalter said after the win.
Pulisic left the field at half-time after sustaining a heavy knock while scoring his match-winning goal.
"I can't say enough positive things about Christian," Berhalter said. "With this new injury it's stressful. I think I have less hair on my head now. But we'll take it and move on and go battle against Holland."
Elsewhere on Tuesday, England marched into the last 16 as Group B winners after Marcus Rashford's double and a Phil Foden strike justified their first starts of the tournament in a 3-0 hammering of an outclassed Wales.
Wales, who needed a four-goal victory in a fixture they had not won since 1984 to reach the knockout phase, defended deeply and frustrated Gareth Southgate's side in a subdued first half at the Ahmad bin Ali Stadium.
But they caved in after the break as a rampant England, who will face Group A runners-up Senegal later, boosted their goals tally in the tournament to nine and fueled hopes of a deep run in Qatar, having reached the semifinals in 2018.
The first-ever all-British clash at a World Cup lacked the drama many had envisaged when Wales sealed their place in Qatar by beating Ukraine in a playoff.
For Wales star Gareth Bale, whose career has scaled dazzling heights, it was an anti-climactic end to his first, and probably last World Cup.
"To be at a World Cup, if you'd asked us that two years ago, we'd have all pinched ourselves," Bale said.
"It's disappointing to go out but we will all walk out of that changing room with our heads held high proud of each other."