His guy played SF and your SF is a $7000 player. Did you switch defensive assignments to make sure he was matched up against your 24K defender?
Even then, as yo mentioned that player may also have high driving/IS and be a bad matchup for your guard with good OD.
Also, his team put more effort into the game. Not sure if that means you played TIE or he Crunched but that's going to change some of the dynamics of that matchup in his favour.