pls answer

Depends on how drunk the 2600+ player is.

ChessExplained has a video of a 1700 rated player beating a gm in an open tournament: https://www.youtube.com/watch?v=91tbGuKVZWk

yes

there is always a chance

Sure, I have beaten an IM a couple of times. Both is casual games and both when he got too involved looking for an elegant mate. But in a tournament game? Not very likely.

no

It's possible. If I were in the right place at the right time, I might have beaten a GM (with USCF around 1400 at the time). I was relatively booked up on the dragon and I had a coach (around 2200) that specialized in the dragon and he wanted to see if I could see a tactic that he once beat a GM with. He showed me the game and we reached a position that I frequently get into (there might have been a different move order so had I sat across from the GM in a tournament, it might not have happened but I'd like to think it would have). The GM played a move that I didn't like for white and the coach asked me what I would have played. The move I picked was the same that he chose and then the GM subtly blundered. I immediately saw ideas that were confirmed when the coach said that he know had a winning move. I thought about it about the same as I would have if he hadn't told me because I smelled blood in the water, and I found it. Basically, the 2200 beat the GM and I would have played the exact same moves as him.

Of course, it might not have happened that way if I was directly playing the GM--I might have gotten nervous and blundered, or he might have played a different line, or he may have not resigned in a "losing" position and I'd have lost even up a bunch of material, but I'd like to think that if I were paired with that GM on that day and the GM thought my rating was 2200, I'd have won.

So it's certainly possible. I'm sure it's happened before.

Yes, I beat a 2100+ rated player in casuals/kibitz with no time controls over the board. I was up a pawn in the middlegame and it went all the way to an endgame where I had K+N+P+P+P+P vs K+N+P+P+P

Yeah, if a Russian GM is sober he will lose.

Is there a chance? Well, according to quantum theory, there's a chance that my coffee cup will simply fall through the table onto the floor. But I wouldn't count on it.

a 2600+ NOT A 2100+

but still need a 2600+ and an

amateur player

Artur Yusupov vs Kevin Gentes (1986)

Saw this game first had in Winnipeg Manitoba Canada Gentes was a local rated player Yusapov at that time was the third highest rated player in the world.Gentes won

Is there a chance that an amateur player will beat a 2600+ GM?

Yes, on a boxing ring, LOL.

thanks achja

Luke McShane is generally referred to as an amateur....

only in a simul.

If by beat you mean beat his face up, then yes it is possible

a lot GM has been beat in a simul by amateurs.

i would love to believe it is possible!