When is the last time a human has beaten a computer in a fair chess game?

A fair match has never been played between humans and computers. Let's say we have a fair match:

    * 100 games, to have some statistical relevance.
    * One move per day, so that being tired is no disadvantage (engine can ponder all day).
    * Human has access to endgame tablebases and opening databases, like the engine.
    * Human can make notes and has a software like Chess Position Trainer, which can min max, like the engine.

If the human is a GM with Elo 2700+ I predict 25 draws and 5 wins for the human. The engine wins 70 games.

From the Stockfish docs at https://official-stockfish.github.io/docs/stockfish-wiki/Sto....

> Rating Stockfish against a human scale, such as FIDE Elo, has become virtually impossible. The gap in strength is so large that a human player cannot secure the necessary draws or wins for an accurate Elo measurement.

[1]: https://computerchess.org.uk/ccrl/4040/

You're way off the mark here on modern engine strength.

There are many examples of top players playing Leela Knight Odds. And none of them even got remotely close to a decent record. Usually a few draws, and maybe a win. But almost entirely losses.

And that is with knight odds. Without that, zero chance.

It technically could happen but hasn’t so far.