Gareth Southgate revealed Harry Maguire was substituted in England's 6-2 win over Iran due to illness rather than injury.

Maguire's inclusion in Southgate's World Cup squad has been fiercely debated after he fell down the pecking order at Manchester United, but he produced a solid performance as England began their Group B campaign in scintillating fashion on Monday.

The defender's aerial presence troubled Iran throughout, and he claimed an assist by nodding down a corner for Bukayo Saka to put England 2-0 up with a brilliant volley in the first half.

Maguire was then replaced by Eric Dier after appearing to go through concussion checks after the break, but Southgate moved to ease any fears regarding his condition after the win.

"Harry Maguire felt ill. [He] flagged it before the [first Iran] goal," Southgate said. "There was no point carrying on, but other than that, no causes for concern."

Writing on Twitter, Maguire said: "I felt unwell in the second half so came off as a precaution. Looking forward to Friday."

Meanwhile, a total of 24 minutes of stoppage time were indicated throughout the game after Iran goalkeeper Alireza Beyranvand suffered a nasty head injury in an early collision with team-mate Majid Hosseini.

While Beyranvand was eventually replaced by Hossein Hosseini, Iran attracted criticism for their initial decision to allow the visibly dazed goalkeeper to continue following the incident.

However, head coach Carlos Queiroz looked to absolve his medical staff of any wrongdoing after the match, saying a broken nose was originally thought to be the extent of Beyranvand's injury.

"We thought he could keep going," Queiroz said. "It was not clear but, one minute after, the player was not able to keep going. 

"He suffered a serious concussion and is on the way to the hospital to have final examinations. 

"That's why the delay happened, because there was doubt between the broken nose and the concussion."