Mainoo, at 19 years and 82 days, became the youngest player to feature in a World Cup or Euros semifinal for England during last night's win against Holland.
He said afterwards: "It's an indescribable feeling, we're all buzzing. It's been such a journey to get here. I feel like we've built on all the performances that we've had leading to this point, and I feel like the only way is up. It's time to put ourselves into history.
"We had the game under control in the middle of the park. And I feel like in the second half we just had to grind it out. It was tough but the whole squad was a help, with the impact off the bench from Cole and Ollie. What a finish!
"My (England journey) has happened quick. But, I've just been taking it day by day, game by game. And now we're in the European Championship final."