Robert Page’s side drew their opener with the United States 1-1 and know three points are vital to make the knockout stages of the tournament.
Here, the PA news agency looks at the main talking points surrounding the clash at Doha’s Ahmad Bin Ali Stadium.
Bale still the main man
— Wales 🏴 (@Cymru) November 21, 2022
The game has changed and those lung-busting unstoppable runs have primarily gone.
But 33-year-old Gareth Bale is still capable of providing match-defining moments and remains the difference for Wales as he prepares to win a record 110th cap against Iran.
Bale both won and scored the penalty against the USA to keep Wales’ hopes of making the last 16 alive.
More Kieffer, please
At 6ft 5ins Kieffer Moore is difficult to miss and the absence of his name from the Wales teamsheet for the opening game was a shock.
Boss Page realised the error of his ways after a futile first 45 minutes and Moore changed Wales’ fortunes after being sent on at half-time, holding the ball up to bring Bale and Aaron Ramsey into play.
Moore must return to the starting line-up on Friday, especially after England showed in their handsome opening 6-2 win that Iran are defensively fragile in the air.
“Give me hope Joe Allen” sing the Wales fans to the tune of Eddy Grant’s “Gimme Hope Jo’anna – and they are hoping the Swansea midfielder is fit enough to play some part after missing their World Cup opener.
The 72-times capped Allen, so fundamental to the way Wales operate, has not played since damaging a hamstring on September 17.
But Allen has stepped up his fitness push over the past few days and joined the main group after spending the first few days in Qatar training on his own.
Will Wales feel the heat?
— Wales 🏴 (@Cymru) November 18, 2022
Wales had the luxury of a 10pm kick-off local time against the United States and playing in cooler conditions.
But the Iran game is first up on Friday, with the action kicking off at 1pm.
The temperature is expected to be around 29 degrees Celsius at kick-off, so will that prove an advantage for Iran players more used to hot conditions?
Whereas England had never played Iran until Monday’s World Cup meeting, Wales have previously met the three-time Asian Cup winners.
A Tehran friendly was arranged in April 1978 as the Liverpool-supporting son of the Shah of Iran wanted to invite a British side to play in the country.
Wales won the game 1-0 with Cardiff’s Phil Dwyer scoring the only goal in front of a 50,000 crowd.