Houston vs. Jardine, shouldl this have been a DQ?

[hermit]

I was watching a KO highlight reel posted on a lesser mma blog and one of the KOs was Houston Alexander's mauling of Keith Jardine. I had seen the fight live and at the time never noticed or thought about it, but if you check out the fight closely, you can see that right before Jardine gets KOd with the uppercut while he's sitting, Alexander knees him in the head while he's downed. The referee was behind Houston at the time, so maybe he didn't see it. I am surprised it wasn't even mentioned after the fight.

During the fight while it's happening, you even hear Goldie say "AND A KNEE" as Houston delivers the knee....to the head of a downed opponent. Watch the video and judge for yourself:

Keith Jardine Vs. Houston Alexander MMA Fight Video UFC 71 Knockout | MMA TKO

I am not a fan of either of these fighters, but I think perhaps this should have been a DQ or NC if it was judged an accident?

What say thee, potatoes?