The sixth round of the World Cup was crucial for the remaining players, since it determined who would compete in the final match for the World Cup. Both the winner and the runner up would qualify for the candidates matches — thus, getting through round six guaranteed the players qualification to the candidates, regardless of the result in the final.
The semi-finals consisted of two matches — Dmitry Andreikin against Evgeny Tomashevsky, and Vladimir Kramnik against Maxime Vachier-Lagrave. The first game of both matches was not exactly interesting: Andreikin and Tomashvesky drew in only fourteen moves, while Vachier-Lagrave and Kramnik only played two more. Naturally some people were disappointed by this; but the players do what they think is in their best interests, and the format has generally resulted in fighting chess. Andreikin clearly has been placing his hopes on the tiebreaks throughout the tournament, while Tomashevsky, having black in this game, did not object to the quick draw; meanwhile, Vachier-Lagrave didn't get much in the opening, and the game was already looking drawish at the end.
In the second game, one of the most interesting endgames of the whole World Cup took place between Kramnik and Vachier-Lagrave. Here I will analyze it in depth. But first let's rewind thirteen years, to the fourth game of the match which Kramnik won against Garry Kasparov:
There are some positions in which a rook, knight and pawn cannot win against a rook, since the defender's king is able to tie up all the pieces. Thirteen years later, Vachier-Lagrave was able to save his game against Kramnik using the same theme:
The other game, Tomashevsky-Andreikin was also drawn, but in a much more placid way. Thus both matches moved to the tiebreaks.
In the tiebreaks, Vachier-Lagrave was crushed as white in the first game by Kramnik. In the second game, Kramnik easily made a draw with the white pieces, thus advancing to the final. The first game of the tiebreaks between Tomashevsky and Andreikin was drawn, with Andreikin once again turning to the solid Queen's Gambit Declined. White inflicted serious weaknesses on the black kingside, but Black was able to keep sufficient pressure on White's own vulnerable points along the open files to hold him at bay.
In their second game, an opposite-colored bishop middlegame was reached, but Tomashevsky strangely avoided exchanging queens, after which the game was likely to be drawn. Keeping the queens on allowed Andreikin to create a strong attack. Thus Tomashevsky had to bow out, after an excellent tournament.