Elanga, 19, has featured eight times for the senior side, including his first Premier League start in the 2-2 draw at Aston Villa last weekend.
After moving to England from his native Sweden in 2013, Elanga joined Hattersley FC who, at the time, were coached by Forder.
The 62-year-old, along with friend and local businessman John Croke, knew that the winger was destined to play at a higher level.
Forder claims that Man City were the first club who expressed their interest in signing Elanga, before a parent and scout made contact with Man United's chief scout after watching him play in a local match.
"(Manchester) City showed interest at first and he had a few training sessions with them," Forder told The Sun.
"I had the Under-14s team then and I really shouldn't have played him – but I wasn't going to let him play for anyone else.
"Straight away I could tell he had something, he was outstanding. He picked the ball up in his own half, went past seven players, around the goalkeeper and side-footed it in. I turned to John and said, 'Did you just see that?'
"One of the parents was a scout and he contacted United's chief scout, who looked at him. I think it was an 8-1 defeat but Anthony was outstanding."
As well as representing the senior side this season, Elanga has starred for United's youth team, scoring five goals and registering three assists in 10 appearances. body check tags ::