Clock: this move took 26.2 s, and 1:33 were left after it.
At move 21 Black's queen on b6 stood behind the bishop on c5, so 21...Be3+ was ready: it checks the king on c1 and attacks the queen on f4, and the queen on b6 defends the bishop. 21.Bd3 did nothing against it, and 21...Be3+ came at once (−8.9).
21.Qe4 moves the queen out of the bishop's reach and keeps the game level (−0.2). 21.Bd3 took 26.2 seconds, with 93.2 seconds left, and White resigned after 21...Be3+.
After the opponent lines up a queen behind a bishop, look at every check that bishop can give and what else it would attack.
Clock: this move took 5.7 s, and 2:47 were left after it.
After the early queen trade Black's king stood on d8 and the knight on d4 stood on the same file as White's rook on d1, so it was pinned. 9...c6 attacked the bishop on b5 but did not unpin: 10.Nxe5 cxb5 11.Ngf3 Ke8 12.Rxd4 and White won the pinned knight (−1.6). 9...Nxe4 takes a pawn and stays close (−0.5).
This is a mistake of about one pawn, not a blunder, but it is the same kind of error that decided other games.
A piece pinned to the king is a target. Count the pieces that can attack it, and unpin before counter-attacking.
Clock: this move took 1.9 s, and 2:43 were left after it.
White's knight on e5 was one jump from c6, a square that attacks both the queen on d8 and the bishop on e7. 10...d4 ignored this and 11.Nc6 won material (−4.2). 10...Bb7 or 10...Re8 limit the damage.
When an enemy knight is near the centre, list the squares it can reach and what they attack.
Clock: this move took 4.7 s, and 1:07 were left after it.
Black was far ahead from the opening (the engine had it above +7 at one point) and the lead drained slowly: 20...Qxc4+ and 25...Na5 each gave back more than a pawn. The decisive step was 27...g6, which allowed 28.Ne7+ forking the king and the rook on c8 (−4.0). 27...Kf8 keeps a small edge (+0.6).
In a winning position, check the opponent's checks, captures and threats before every move, and keep simplifying.
Clock: this move took 1.9 s, and 2:34 were left after it.
On f5 the knight stood on the same diagonal as the king on c8, and White's bishop could reach g4 with a pin. After 21.Bg4 the knight is lost even though Black unpins with ...Kb8, because 22.Bxf5 follows (−4.9). 20...Kb7 or 20...Ng6 avoid the problem.
Before placing a piece on a diagonal or file that points at your king, check whether an enemy piece can pin it.
Clock: this move took 2.8 s, and 2:57 were left after it.
5...d6 emptied the d7 square, so White's bishop on b5 pinned the knight on c6 to the king. After 6.d5 the pinned knight had nowhere to go: the engine already rates the position −1.9, and the game continued 6...O-O 7.dxc6 with a piece lost. 5...exd4 settles the centre and keeps the position level (−0.2).
Before moving a pawn in front of a piece, ask which line it opens or closes. Here the d-pawn was the only thing between the bishop and the king.
Clock: this move took 1.4 s, and 56.0 s were left after it.
At move 33 Black was clearly ahead (+6.0). 33...Rxc7 took the pawn, but the rook on c7 had no defender, and the engine's reply 34.Ne6+ checks the king on g7 and attacks the rook at the same time (−5.8).
White played 34.Nxa6 instead, and Black went on to win. The capture took 1.4 seconds, with 56.0 seconds left against White's 16.2. 33...a5 keeps the lead (+6.0).
Before putting a piece on a square, check which knight checks the opponent has and what else they would attack.
Clock: this move took 1.3 s, and 2:36 were left after it.
At move 7 the black knight on f6 and bishop on d6 both stood on the sixth rank, two squares apart, and 7.e5 attacks both. The pawn on e5 is defended by the knight on f3 and the bishop on b2, and after Black's best reply 7...Be7 the line 8.exf6 Bxf6 wins a piece for a pawn (+4.4).
7.O-O was played instead (−0.5), and 7...Bb8 took the bishop off d6, so the fork was gone. Castling took 1.3 seconds by the clock readings.
When two enemy pieces stand on the same rank two squares apart, look for a pawn push between them that attacks both.