Single table tourney. 3 of us left...me with the chip lead. Dealt A8 suited spades in the big blind. Button limps in, small blind calls, I make a pot sized raise. Button folds, small blind calls. Flop comes 2 of spades, 5 of spades, Jack of hearts. Small blind checks, I make another big raise with my nut flush draw. Small blind calls, turn is 9 of spades. Bingo.. I hit the nut flush. Small blind makes a pot sized bet, I raise the small blind all in figuring he had a set of 2's or 5's or Jacks. He calls with 5,2 offsuit. River comes...you guessed it..2 of diamonds. He makes 2's full of 5's and takes most of my chips. I finish 3rd place in a tourney I should have won. I'm still scratching my head as to why he called my preflop raise with 5,2 offsuit.