This is Hatton knocking out Maussa with his Floyd Patterson style 'Gazelle punch'.
Here's the original, Patterson's 'Gazelle Punch'. The particular punch in question is about 30-32 seconds in.
Another comparison I have found is the knockdown of Collazo in the first round.
It looks just like Tyson's fourth round knockdown of James 'Quick' Tillis.
Anyone else got anymore of these. I'm sure there's some pernell Whitaker /Floyd Mayweather ones out there.