Manchester United captain Maguire, 29, was deployed in a three-man defence as the Three Lions travelled to San Siro in the Nations League on Friday night. While it was no surprise to see the centre-back start in Milan, his place in the side has been called into question due to his lack of Premier League minutes this season.
Maguire has lost his place in the United starting XI - with Erik ten Hag preferring Raphael Varane and Lisandro Martinez - leading many to suspect his place in the England line-up could be up for grabs by the time the World Cup rolls around in under two months' time. Cole understands why Southgate has stood by his under-pressure defender, but confesses it is a "huge decision" to keep playing him.
"It is a huge decision by Gareth and a huge show of faith because this team and this group has been built on the foundations that they must be playing at your club and you must be playing well," Cole told Channel 4 of Maguire's inclusion in the starting XI. "And that has galvanised the group and given them that togetherness to go out and play well.
"And Gareth has come away from that because Harry has played so well under him, and that is the first time he has done that."
Such is Southgate's belief in Maguire, he declared he would put his "reputation" on the line by continuing to select him for England. Speaking ahead of the clash with Italy, the Three Lions boss said: "Whatever reputation I have, I'm putting it on there. I think, look, you always have to back your judgement and we feel Harry is an important player.
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"If we thought there were experienced players ready to step in and play at a level above him there would be a different consideration and in some positions there would be a different level of competition in that way.
"He is our most dominant aerial centre-back. He is an important player for us. I think it's important to back our best players."
Against Italy, Maguire lined up alongside Kyle Walker and Eric Dier at centre-back, with John Stones suspended for the fixture. Walker and Dier have been in fine form for Manchester City and Tottenham respectively this season and may well form part of the first-choice backline in Qatar, although Southgate may choose to stick with Stones - who started the Euro 2020 final against Italy last year - over the latter.