Yangyi under heavy pressure
Yangyi has taken great risk in the opening to try to give himself chances to win, but Niemann has handled the situation brilliantly. Yangyi is now the one who is forced on the defensive, while Niemann will only need a draw to ensure his place in the round of 4.
Niemann has decided to take the pragmatic approach, trading down to an equal endgame rather than playing for a winning attack. While Yangyi currently has an extra pawn, his damaged pawn structure on the kingside makes a draw the by far most likely result.
Niemann gives up his rook to get rid of Yangyi's dangerous passed pawn, leaving him with connected, passed pawns against Yangyi's rook. This should be a clear draw with best play.
Niemann goes wrong, and Yangyi gets a golden opportunity out of nowhere! Niemann's misstep will allow Yangyi time get his king into a defensive posture, and Yangyi suddenly has a winning position!
Niemann loses control and loses!!
In an astonishing turn of events, Niemann goes wrong in what seemed like a trivially drawing endgame! Yangyi does the impossible and wins on command after Niemann's endgame blunder allowed Yangyi to stop his pawns just in time. After Niemann's surprising blunder, we're suddenly heading into armageddon!