(I'm not going to say Kasparov but I did play him at a simul more than ten years ago now. But it was a simul, not a "real" tournament game.)
The Real Game?
I don't recall his name, but he was the New Mexico State champion and rated, at the time, 2413.
It was a real over-the-board 40/2 tournament, I had managed to defeat three players rated about 1900, 2000, 2200 - I remember that because I was paired against progressively stronger players.
When I played the State champion all his friends/acquaintances looked on with admiring looks to him and scorn to me.
I managed a quite respectable Sicilian Defense and had a decent middlegame but this fellow was slowly trading me into an easily won endgame. To outsiders, it might have looked close, material was even after all, but I could see that he'd be able to force me into zugswang and easily queen a pawn.
A fun game but more because I was not crushed and didn't make a huge blunder. He generously analyzed the game but it was obvious that what was a life and death struggle for me was simply a sterile drill for him: he knew the ending was going to lead to a small advantage for weaker players but a huge advantage to a master.