Roller coaster game

This is a game I played earlier tonight and lost.  I had great winning chances early on but my opponent played the endgame like a champ and I played it like a chump.  My opponent was an absolute shark at the board. I'm rated 1500 in real life this guy is provisional but is easily a Class A player but he hasnt played a rated game in six years he says.  You'll see early on he's playing some inferior opening moves but when we get to the endgame he turns into a monster.  I was told by some other club members he has beaten a rated Expert, our former state champion and another Class A player in our club in casual games in the past.  He was clearly just flat out better than me.  Oh and here's the kicker... he's provisionally rated 1150

Your input and feedback is appreciated (as long as you're not mean to me... I'm sensitve.)

I'm Playing White

Not sure why the game stopped at move 48.  I put in 50 something moves. Anyways, Black converts obviously.

I know the feeling.  I recently played a tournament game against a guy that hadn't played a rated game in 8 years.  His rating from then was 800, but he certainly played better than that.

The wisdom here is to play the position and ask about ratings afterwards...