I don't want to play when the rating is 1700 and makes 0 mistakes.

I don't understand why such opponents don't play at level 2200? Why do they have a low rating but a high percentage of game quality? It looks like cheaters, but I can’t make a report without justifying my opinion. The opponent makes 0 mistakes in an unfamiliar opening. Takes pawn after pawn like a harvester. 95% accuracy. And this is not an isolated case; such rivals meet all the time.
It becomes so sad that I don’t want to play anymore.

Because even players under 1700 can play a mistake-free game according to Lichess engine criteria. Just not all the time. You can even play a game with zero mistakes and still lose. I've ended up in a losing position within about 15 moves with zero mistakes.

The definition of a "mistake" is almost arbitrary. It's based on the engine's assessment of how centipawn losses translate to winning probabilities, but deciding what percentage drop constitutes an inaccuracy versus a mistake is more of an art than a science.

@RemRus said ^

The opponent makes 0 mistakes in an unfamiliar opening. Takes pawn after pawn like a harvester.

First of all, thx for making me chuckle, RantRus!

How can u read the opponent’s mind? Know what’s familiar to them and not? I think I need to report you for cheating with superhuman powers!

@RemRus said ^

I don't understand why such opponents don't play at level 2200? Why do they have a low rating but a high percentage of game quality? It looks like cheaters, but I can’t make a report without justifying my opinion. The opponent makes 0 mistakes in an unfamiliar opening. Takes pawn after pawn like a harvester. 95% accuracy. And this is not an isolated case; such rivals meet all the time.
It ...

I've had games with 99% accuracy, unless it happens all the time it doesn't mean anything. People need to learn this fact it's not hard to understand.

For good measure, here you are playing with 98% accuracy not even a single mistake, did you need to be reported too?

'The opponent makes 0 mistakes in an unfamiliar opening.'
Unfamiliar to you, but maybe not to them.
'Takes pawn after pawn like a harvester.'
Thank you for the kind presents.
'95% accuracy.'
A winning position will remain a winning position unless there is a blunder.

Of course, they may be cheating but in order not to get caught they only cheat against you.

@lonelypeanut said ^

here you are playing with 98% accuracy not even a single mistake

This is a rare case. I would love to play 9 out of 10 games like this and be 2200. But I make mistakes and couldn't get to 1900. I don't understand how to beat someone who doesn't make mistakes?

There would be less such cases, if online platforms would ban having multiple accouns, there are people sandbagging, playing many different accounts for practice etc, if there was allowed only on account per IP or something, these training accounts would not exist, and the playing field would level out

If you make a significant mistake early on, like losing a pawn, it does not sound surprising that someone with a roughly equal rating will tend to crush you for the rest of the game, and thus get near perfect accuracy.

Note that if they have a very won position and play a suboptimal move, that does not mean they lose accuracy as the position after their move is likely still very won.

I wouldn't worry too much about cheaters, but if you really want do do some detective work:

1. Take some games of the player
2. Eliminate the opening and clearly won (or lost) sections, like positions with more than +-1 evaluation
3. Start counting how often they play the absolute highest recommended engine move

If you see 5 deviations in less than 5 games with 20+ moves in an equal positions, it is very likely they are not an engine player.
If you see this ratio actually holds for their last 20 games, then i wonder how they manage to stay 1700 unless they do something very weird to shed rating...