Wales international Ampadu was also eligible to play for England, and even played for the Under-16s in 2015, with his former Exeter manager Tisdale alerting The FA to take notice of his development when he was 14 years old.
"I haven't seen a 14-year-old as good as Ethan Ampadu," Tisdale told BBC 5 Live. "I mean I actually phoned England to make it known.
"I spoke to very relevant people and said, 'you've got to get a hold of this chap. He's such a good player.'
"I think there's always been a hesitation to listen to someone talking about a player from League Two.
"But this is not a league thing, this is not about league level. A player's a player. I did phone England when he was 14.
"I said, 'I've just seen this chap play, he's 14, he just played for Exeter Under-18s, he's four years younger, he's played on a dreadful pitch with awful conditions and he's played centre forward, sweeper, centre midfield all in the space of one game.
"'He looks like Ruud Gullit and this chap, you need to get for England.'
"I was told they had better. I was told they had 12 players better, they were aware of Ethan and, well, I said, 'this chap just, he thinks correctly, he acts correctly, he makes good decisions,' and I was told that he takes too few touches.
"They were looking for players who want to take more touches, which is actually his strength. He does things in one touch, two touch, he sees it early."