Location, location, location.
As far as it sounds, your only problem was that you were not in the swim next door. How many times I have been in a situation fishing 2 or 3 rods, and I have caught several fish all on the same rod. There are many many variables of location in your own swim, let alone comparing to the swim next door. I wouldn't beat yourself up, one fish is a successfull session, don't worry about what you did wrong, but try to realise everything that you did right.