http://www.buzzerbeater.com/match/52662812/boxscore.aspx
http://www.buzzerbeater.com/match/52662828/boxscore.aspx
http://www.buzzerbeater.com/match/52662860/boxscore.aspx This one while playing at PF vs a PF no less, in a 2-3 zone format
The third one is under different conditions, so you can't really use it to compare guard performances. In any case, out of the 6 guards that started for your opponent in these 3 games, 5 of them have 11k or lower salaries. The sixth is a 60k guy who now has average GS and had ratings of 11 and 11.5 in this week's games. When he played against you his rating was 8.5, so I imagine his GS was even worse then. Your guy did have a nice game (16 assists) that time, but he was playing against a full court press of guys in terrible shape, which is probably the best recipe for disaster.
Like I said, and Kumiko added to it, a player may outplay a higher-salary opponent if he has better GS, secondaries, is played in a good tactic, etc. But if both players have "traditional" skills distributions, the guy with the highest salary will have the better skill-set and perform better under the same circumstances.