Lessons From Bad Bertrich: Dizziness Due To Success

IN round seven I faced a Fide master, gaining a winning position (Stockfish17) or at least the upper hand (Dragon1) before move 30.

White has just played 28.Qd2-h6 in Spanton (1946) - Markus Balduan (2247)

But I threw my advantage away with an ill-considered 34th move, although at the time I thought I was still winning, before blundering in the following position.

Black has just played 38...c4

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My reply 39.Rb4?? (39.Re3 was necessary) was met by 39...Qb6+, when Black's advantage is worth almost a rook, according to the engines.

The game finished: 40.Kg2 Qe3 41.Rbb1 Qxg5+ 42.Kf1 Nf6 43.Qg7 Rg8 44.h4 Qf4 0-1

In his famous book Think Like A Grandmaster, Alexander Kotov devoted a section to Dizziness Due To Success, which probably trails only The Tree Of Analysis for being well-known.
Kotov recounted a game in which he blundered horribly, partly out of annoyance that his opponent had not done the decent thing and resigned.
Shortly after that game finished, with Kotov's resignation, he read of a similar fate befalling Alexanderr Ilyin Zhenevsky.
Kotov wrote: "The main reason for the two blunders was the lowering of vigilance that can go with the recognition that the win is near."

He called such a phenomenon "dizziness due to success," paraphrasing - apparently without any intended irony - the title of a Joseph Stalin article in Pravda on agricultural collectivisation.

LESSON: just as a football team is often most vulnerable immediately after scoring, so chessplayers are most likely to let their vigilance down after gaining a decisive advantage.