From what I can tell, the engine he plays, Rybka, is an alpha beta search engine that is rated around 3000 elo? I'm not sure how to compare it with Hikaru being

From what I can tell, the engine he plays, Rybka, is an alpha beta search engine that is rated around 3000 elo? I'm not sure how to compare it with Hikaru being ~2900, but it seems like a fairly "even" match-up without a crucial exploit being the reason for it losing.