In bravely scoring the winner for his country shortly before half-time, Pulisic picked up a heavy knock and had to replaced at the interval. He will hope to be fit for the USA’s knockout clash with the Netherlands on Saturday.

Taking place simultaneously in Doha, England eased past Wales 3-0, all the goals coming in the second half. The Chelsea trio of Mason Mount, Raheem Sterling and Conor Gallagher remained on the bench, with the Three Lions’ focus now turning to a last-16 tie against Edouard Mendy and Kalidou Koulibaly's Senegal on Sunday evening.

The destiny of both the US and Iran was in their hands, both sides knowing a win would secure involvement at this World Cup beyond the group stage.

The US switched back to the 4-3-3 shape they used in the draw with Wales, so Pulisic was positioned wide on the left at the Al Thumama Stadium. He signalled the States’ intent in just the second minute with a driving run at the heart of the Iranian defence, having stolen possession inside his own half, and it was our man who had the game’s first on-target effort.

Attacking Yunus Musah’s cross on 11 minutes, he outjumped his defender and got good contact on his header, but it was too close to Alireza Beyranvand in the Iran goal.

USA were playing like a team that knew they had to win, using their overlapping full-backs to good effect and getting plenty of numbers in the box. Pulisic had something of a free reign, regularly dropping deep to receive possession or moving infield to offer a threat nearer the goal.

It was from exactly that scenario Pulisic put the US ahead. A brilliant diagonal pass from Weston McKennie found Sergio Dest who headed across goal first time. Pulisic showed great desire and speed to reach the ball ahead of Iran’s centre-backs, guiding the ball into the net from six yards out. Pulisic’s 22nd international goal was his most important yet.

It did come at a cost, though, as he and Beyranvand collided after he had fired the ball past the Iran keeper. Pulisic needed lengthy treatment for what looked like a bang to the hip and left leg, but was able to get back on the field before half-time, albeit moving gingerly. Before the whistle blew, in the sixth minute of added time, Timothy Weah had the ball in the net for the US with a deft finish but was fractionally offside.

Pulisic couldn’t shake off his injury, unfortunately, and had to be replaced by Leeds’ Brenden Aaronson before play restarted.

Iran had their first attempt of the game five minutes into the second half through a sub of their own, Saman Ghoddos, but the US largely kept their opponents at arm’s length, controlled if never entirely comfortable.

They defended resolutely when required and over the course of their three group games will feel they thoroughly merit their place in the round of 16 having not been beaten and won the crunch game when it mattered.

There were two late scares for the US in nine additional minutes, the first when Morteza Pouraliganji’s diving header flashed just wide of the near post, and the second after a VAR check with Medhi Tahremi claiming he had been tugged back in trying to poke the ball into the net. No foul was given so Pulisic’s first-half contribution proved decisive.

In Al Rayyan, England made light work of Wales to guarantee top spot in Group B.

Gareth Southgate dropped both Mason Mount and Raheem Sterling to the bench, Marcus Rashford and Phil Foden two of four fresh faces in the England side.

Wales knew they had to win to stand any chance of advancing, and their manager Rob Page moved to a back four. That meant Ampadu had an extra man alongside him in midfield, the veteran Joe Allen.

In the first World Cup meeting between these neighbours, Rashford had a big chance to put England ahead in the 10th minute, denied by Danny Ward in the Welsh goal after Harry Kane had slipped him through.

Foden shot over after swivelling inside the box as England dominated territory and possession without being able to break down a typically dogged Welsh backline, regularly supplemented by Ampadu’s defensive nous and bravery.

Going forward their ambition was limited, though, restricted to one Allen shot curled well over Jordan Pickford’s bar in added time. They did not have one touch inside the England box in the first half.

Their task became harder four minutes into the second when Rashford whipped a free-kick into the top corner, and it was 2-0 just 98 seconds later, Foden converting Kane’s inviting low centre.

Rashford added a third midway through the second half, racing on to a long ball, cutting inside and firing through Ward’s legs. By now Ampadu had moved to right-back as the game petered out, England satisfied with their night's work and Wales unable to source a consolation.