Apparently there is gas in the tank when I need it

Ran a quick 10k today before the rains came. I was feeling out of it a bit, more lethargic but nothing serious. I was a little sore from the run yesterday but was making more out of it than needed to which almost made me not want to run. Nevertheless, I set out on my usual route and just went running. I clicked off the first km easy then slipped into a groove that was oh so sweet. I cruised along for 4 more km like that, then worked up the one long climb and then tried to find the groove again. The last km was tough, up hill and fatigued but I really worked it, finishing alot faster than I figured I would. When I pushed it, there was still plenty left to spare. Good times. 46:55 ~ 10.2km, 4:36 per km.