After keeping their World Cup hopes alive by defeating Wales dramatically on Friday, Iran face an impressive USA side at the Al Thumama Stadium on Tuesday, with three points enough to take either team through to the knockout stages.
Team Melli looked like a different team against Rob Page's men to the one that was thrashed by England in their opening game, whereas the Stars and Stripes will be rueing missed chances that forced them to share the points with the Three Lions last time out.
Iran seemed to be back to the performance levels that earned them a place at the World Cup during the 2-0 victory over Wales, with any ideas of Team Melli being the whipping boys of the group after a heavy defeat to England swiftly banished thanks to late goals from Roozbeh Cheshmi and Ramin Rezaeian.
The availability from the start of Bayer Leverkusen forward Sardar Azmoun against Wales gave Carlos Queiroz's side more attacking threat, with the 27-year-old combining well with talisman Mehdi Taremi who unlike the first match of the group had a capable partner in crime at the top end of the pitch.
Azmoun has been sidelined for his club side since early October with a calf injury and was down receiving treatment on three separate occasions before miraculously rising to his feet to continue, with the 40-goal international eventually being forced off after 68 minutes as his side chased a winner.
Now sitting second in Group B with three points from two matches, Iran know a win against USA secures passage to the knockout stages of the World Cup for the first time in their history - although even a draw on Tuesday would be enough if Wales fail to beat England.
Fellow Asian qualifiers Japan and Saudi Arabia have caused significant upsets within the first week of this World Cup, and Iran could add to the success stories from that region by advancing past the group stages for the first time on Tuesday night.
Despite not being able to return maximum points from any of their two opening games at this tournament, Gregg Berhalter's USA side have shown they are set to be a new prospect in international football with a young crop of energetic and athletic stars.
After decades of Americans competing at the top level in Europe being a rare sight, 10 such players donned the stars and stripes on Friday night and overran England for large parts of the encounter, with only poor finishing preventing Berhalter's men from earning their first World Cup win over the Three Lions since 1950.
Weston McKennie blasted a strike over from inside the box after evading the attention of Bukayo Saka, whilst shortly after Christian Pulisic struck the bar with a ferocious effort which had Jordan Pickford scrambling to deflect the ball away from goal.
What really stood out for USA was their athleticism and sharpness compared to their English counterparts, with full-backs Sergino Dest and Fulham's Antonee Robinson providing pace on the wings whilst Tyler Adams kept Jude Bellingham and Mason Mount under wraps in the midfield.
A knockout tie with either Netherlands, Ecuador or Senegal awaits Berhalter's side should they defeat Iran on Tuesday, and if the Stars and Stripes can find their ruthlessness in front of goal they could be a real threat to the elite nations in the latter stages of this competition.
Iran will be without the services of Alireza Jahanbakhsh in their final game of Group B as the former Brighton & Hove Albion man received a second yellow card of the tournament after a high-footed challenge on Wales' Chris Mepham during the closing stages of proceedings on Friday afternoon.
Star man Azmoun is a doubt for Team Melli after visibly struggling throughout his 68 minutes on the pitch against Wales, although Queiroz may risk the attacker from the start on Tuesday considering how much quality he adds to the side.
Alireza Beiranvand sat out of the Wales clash due to concussion protocol after a nasty head injury in Iran's first match of the World Cup with England, but the 30-year-old is available to return in this vital fixture if Queiroz decides to drop Hossein Hosseini, who kept a clean sheet on Friday.
USA have no fresh injury concerns ahead of Tuesday's match, with the large majority of fan and media attention focused on the lack of gametime for Borussia Dortmund's Giovanni Reyna, who has only seen 15 minutes of World Cup action so far.
Haji Wright replaced Josh Sargent in the USA starting XI against England in the only change from the Wales match, with the striker position for the Americans yet to find a consistent occupier as Berhalter attempts to discover his side's clinical touch.
Leeds United's Brenden Aaronson has played his part off the bench in the last two matches and looks set for a similar role on Tuesday with a midfield trio of Adams, McKennie and Yunus Musah impressing massively so far in this World Cup.
Iran possible starting lineup:
H Hosseini; Rezaeian, M Hosseini, Pouraliganji, Mohammadi; Ali Gholizadeh, Nourollahi, Ezatolahi, Hajsafi; Taremi, Azmoun
USA possible starting lineup:
Turner; Dest, Zimmerman, Ream, Robinson; Adams, Musah, McKennie; Pulisic, Weah, Wright
We say: Iran 0-1 USA
Iran are back on track in this World Cup after a worrying start against England, but now face a USA side who look a challenge for any team in this year's competition.
Berhalter's men are yet to accompany three points with their energetic performances, but should have enough to secure passage to the knockout stages against an Iranian team who may be without Azmoun.
For data analysis of the most likely results, scorelines and more for this match please click here.