I thought I played poorly, but not as bad as opp (2/5 NL live game)

[PokerSlut]

I'm in MP w/AJo (~$450), and open at 20. One fold, CO (~$300) calls, and Button ($250) calls. CO is typically very loose PF but will fold to any aggression after the flop unless he has a decent hand. Button seems loose/passive and chases a lot of flushes and straights for poor odds, but also tends to be aggressive with top pair, even with weak kickers.

As the dealer is turning the cards over, both my opponents are staring attentively at the spot on the table where they will soon appear. I keep my eyes on them and gauge their reactions to the flop. CO is obviously disappointed and probably has small cards or a suited ace. Button's shoulders slack as he stares at the flop apparently trying to change the cards by force of will. I look at the cards.

Flop is Q94r

I lead out for $45, CO folds, and Button calls.

Turn is a 7, completing rainbow.

I bet $75. He hesitates a few seconds and calls.

River is a 2. I check, he thinks a few seconds, and checks behind.

I show my AJo, and it wins.

Anyone care to guess what my opponent showed?