If it's only running on one cylinder then it's unlikely that the main connections of the fuel system are at fault.
Although the plug is sparking, it could be so weak as to get "blown" out by the compression pressure in the cylinder, so a new plug is worth trying.
If fuel can be smelt, it's again, unlikely to be a fuelling problem, which again points to ignition.
Only other thing which springs to mind at the moment, it's been a long day
, is maybe a valve has burnt or been bounced with the high revs. Pretty unlikely, but a compression check would dispell/prove this.