Did I horribly mangle this hand? 10$ on stars

I've played alot more cash games then tournaments, but want to get better at tournies. I don't have too much experience near the end of big tournies, especially with a big stack. I had a real good chance to win my first big mtt today, but I think I might have blown it. Anyway today I was in a 10$ tourney on stars, with 850 entrants.

When this hand came up I was far and away the chip leader with 67k, when the average was ~12k. I had been playing very aggressively stealing blinds, when it was folded to me in the SB. The blinds were 400/800 with 50 ante, and the BB had 25k. I raised to 2000 with k/2 offsuit and he called. The flop was k/6/9 with 2 spades (i had none). I bet out 2000 and he raised me to 6400. I hadn't seen this guy play very aggressively at all, or seen any possible bluffs so should I have given this raise a lot of respect? Anyway I considered whether he might be bluffing an aggressive chip leader, or raising with a flush draw or some kind of pair, and I thought my kings were good so I raised to 14000. I think i read recently that blind play is a lot like heads-up, so folding top pair would be pretty weak (is this valid thinking or not?) Anyway he went allin for his last 10k, and I pretty much had to call getting 3:1 on my money. Turns out he had K/Q and had me outkicked. Losing this pot hurt a lot, now I think I could have folded to his flop raise and just continued stealing blinds with my huge stack, instead of playing a big pot? Anyway I went from dreaming of winning 2200$ to winning 35$...are tournaments always so frustrating [img]/images/graemlins/frown.gif[/img]

[RIDGE45]

"I hadn't seen this guy play very aggressively at all"

There is your key to fold right there. If you had only seen him raising with legit hands then you what are you hoping ot beat with K5 off? You only beat a bluff. Not worth that risk at that point in the tourny IMO. If he was bluffing I don't think this is the hand you want to take a stand with.