Having embarrassed Samoa and Leicester Tigers hardman Alesana Tuilagi last Wednesday, the 22-year-old flyer did the same to Bryan Habana - arguably the world's top winger - in the Eagles' 64-15 defeat to South Africa in Pool A.
One of the main aims of most of the amateurs in the US World Cup squad would have been to do enough in the tournament to secure a professional contract overseas.
The jet-heeled Ngwenya has definitely done that, and it is no surprise to hear him claim he has already been approached by two English clubs.
And it is almost certain that the Dallas winger will complete a move to Europe - to either England or France - in the near future.
"Hopefully, we will see how it goes," said the shy Zimbabwe-born Ngwenya.
"That's a killer question, England or France? It depends which team I'll be going to.
"It's hard to say now because I am not sure. But in England, so far I have got two (offers).
"It depends. I just want to play better rugby."
The duel between Ngwenya and Habana was always going to be a fascinating one, and it provided arguably the moment of the tournament in the first half of Sunday's clash in Montpellier.
Habana had just gone over in Ngwenya's corner to put South Africa 24-3 up when flanker Todd Clever launched a breakaway from the Eagles' 22.
Via Mike Hercus, the ball ended up in the hands of Ngwenya, who found himself one on one with Habana.
Ngwenya teased his opposite number by feinting inside, before dabbing on the accelerator and flying past Habana on the outside to ground under the posts.
It brought the crowd to their feet and was probably the try of the World Cup so far.