Lessons From Cap Negret IX

MY round-nine game, where I had black against Alberto Pastor Alonso de Prada (2000), reached the following position on move seven of a Réti.

White has just castled

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Usually in such Réti positions, White plays an early d3. I decided to punish his omission of this move by playing ...d3 myself.

But 7...d3? turns a slightly advantageous position, according to Stockfish17.1 and Dragon1, into a lost one (Stockfish17.1), or at least one in which White has the upper hand (Dragon1).

LESSON: greed in grabbing a poisoned pawn in the opening is a well-known phenomenon, but it is also possible to be greedy in grabbing space.