Ngumoha was given around 20 minutes as a replacement for Mohamed Salah as Slot sought a late winner.
The manager said afterwards: "He has incredible potential, otherwise at 17 years of age you don't play as many minutes as he does in the Premier League, let alone at Liverpool. I don't think there's any other 17-year-old that has played so many minutes this season in the Premier League as he did.
"I don't think there is an 18- or 19-year-old maybe that played so many minutes as he did, but that last thing I'm not 100 per cent sure about. So that tells you how much of a talent he is and we think he is. He's making progress more and more and that's why lately you see him playing more and as well.
"He gets stronger. Apart from his moment where he had that one-v-one, there were also one or two other moments where he showed that he stands his ground. That is, of course, what you need because you face 25-, 26-, 27-, 28-year-old athletes mainly as your opponents. We're a bit of an exception in terms of the age of our group of players, most teams we face have players of different ages and different physicality.
"For him to show this already at 17 years of age says something about his talent. But as we all know, talent is only the start of a career and you need so many other things, as we've shown today – Macca (is) a great example about mentality. That is something you need to get a career at this level."