Milan defeated Liverpool 4-2 in Hong Kong on Saturday.
Elliott said of 16 year-old Ngumoha: "I mean, he's fearless – I think he showed that today against AC Milan, one of Europe's big teams. "He just looked like a kid in a park, although he is a kid!
"He just needs to carry on like that and we're trying as much as we can to help him out.
"I think if he keeps on performing the way he is, working hard as he is, the kid's got an amazing future and really excited to see where things go. Hopefully he can be very successful."
Elliott also played with £125m signing Florian Wirtz for the first time on the night.
He said, "I think it was just learning to have that relationship with Flo. When one drops, one stays high and pins back the defenders. If the ball was on one side, make sure we're both coming over to support.
"I think we had a really good relationship for the first time playing with each other and I think it clicked really well. I think we had a fair few opportunities and we were able to cause problems.
"I think it was a really good test in really, really tough conditions against an incredible team as well."