Hikaru analyzed some of Niemann’s games and at certain points he was very surprised by the move, but said that if he was told that there was a strong winning move in that position he would have found the move easily.

Kind of similar to what Magnus said that he wouldn’t even need the move, just a hint like “strong winning move on the board” would be enough for him to find the winning line because he wouldn’t have to look at defensive or passive moves.