Top Pair Decent Kicker OTB - Mistake?

[ericlambi]

Wish I had the HH for this, but here goes. 4 players left in PP $20+2:

Villain (T3500) Posts BB - $200
Hero (T2200) Posts SB - $100
SmallStack1 (T1400)
SmallStack2 (T900)

SmallStack1 folds, SmallStack2 folds.

I have KJo and raise to 600. Villain calls. Flop

K95r

I bet out 600. Villain calls. Turn is random card. Pot has 2400, I have 1000. I push. Villain calls. River comes and villain turns over K5 (soooooted of course).

Was this a mistake or bad luck? I probably could have cruised into the money if I hadn't gotten involved with the big stack. The others were playing tight waiting for someone else to leave . . . could have taken chips from them pretty easily. I don't know at which point I get away from this hand though if it was a mistake.