The West Ham United star was playing non-league football for Tooting & Mitcham United just a few years ago and the 26-year-old is now on the verge of making his England bow after being included in the Three Lions squad for their 2018 World Cup qualifier against Slovakia this Sunday.
Antonio's meteoric rise has been nothing short of sensational but his former manager Coppell, who bought him from the non-league to Reading for just £10,000 back in 2008, has gone on to reveal that the winger is anything but an overnight success.
The former Manchester United star told the Daily Mirror: "I went to watch him play probably a couple of times and he did have something different and it was always the difference that appealed to me with non-league players.
"It would maybe sound wrong to say it now but there was something refreshingly naïve about him in terms of his attitude, his manner, his ability.
"I could tell he had something that would make him be better, that would progress him but I didn't know how far it would take him.
"He had a willingness to learn from day one. He was a very quiet boy in those days. You didn't even know he was in the room but you got the impression that he was watching and learning all the time and since then he has just progressed and progressed.
"It has not been an overnight success. He has had to work for everything he has achieved and this is another part of his process."