Your opponent in that game has only played 11 games total so his rating changes quickly.
Look at his history: http://www.chess.com/home/game_archive?show=live_blitz&member=lasker_em
I don't know what round of the tournament you were in, but he was only rated 1445 at the start of the day, and was probably legitimately under 1500 when the tourney started.
I played in a 5-0 blitz tourney right now for players rated up to 1499. I just got beat by a player with a rating of 1607.
How is that possible?