Jude Bellingham got them up and running just after the half hour mark with his first Three Lions goal, before Saka fired home brilliantly and Raheem Sterling extended the advantage further before the break.
The Arsenal forward got his second, and England’s fourth, with the help of a slight deflection, before Mehdi Taremi lashed home a consolation for Iran as they made a rare foray forward. Marcus Rashford came off the bench and scored, his strike coming seconds after he was introduced, before Jack Grealish capped a memorable World Cup opener with the simplest of finishes.
There was still time for VAR to award Iran a very soft penalty, not that Taremi was too concerned with that as he sent Jordan Pickford the wrong way with the final kick of the match.
England dominated possession as expected from the opening moments, the only disruption to them coming in the form of a serious head injury to Iranian goalkeeper Alireza Beiranvand. After almost ten minutes of treatment he was allowed to continue in a farcical episode, before going down almost immediately as he was then stretchered off.
The established pattern of play was resumed upon the restart, and England were denied by the woodwork as Harry Maguire thundered a header against the bar. The Three Lions took the lead shortly after though, when Bellingham scored his first international goal, heading home brilliantly from Luke Shaw’s cross.
Complete control came England’s way when the advantage was doubled, Maguire involved again as he nodded a corner down to Saka and the Arsenal man lashed a superb finish into the top corner. Three minutes later and the scoreboard was troubled again, Harry Kane turning his man and firing a ball into the box, where Sterling volleyed home emphatically.
Saka got his second of the match with just over an hour played, drifting inside into the box on his left foot and his shot found a way through the mass of bodies, taking a slight deflection on its way into the bottom corner.
The Iran fans in the stands, of which there were plenty, at last had something to cheer, as the ball was played through to Taremi and he hammered a brilliant finish off the underside of the bar to beat Jordan Pickford.
Normal service was quickly resumed though, a matter of moments after Gareth Southgate made four changes. Rashford was one of those and made an immediate impact, working the ball onto his left foot and rolling the ball past the goalkeeper.
As the clock ticked into stoppage-time, Grealish capped a perfect afternoon for England. Bellingham played Callum Wilson clean through on goal, and the Newcastle striker was admirably unselfish in rolling the ball across for Grealish to finish into an empty net.
VAR then intervened in the 102nd minute to award Iran a penalty in slightly bizarre circumstances. Taremi stepped up and dispatched it with minimal fuss for his second of the night, though it did little to dampen the England mood.