Isn't this way supposed to be slower...

When I run a looping route, say clockwise, it leaves me another run some other day, say counterclockwise. So two days ago I ran the said clockwise way in a respectable time. Today, same route but backwards. Are you following me? The route run this way has considerably more uphill than down. But strangely enough, I ran it faster, not by much but a little bit quicker. I felt great, the wind was down and it was about 4C. I wore a sock that rode up higher on my shin to help defuse the rubbing of the tendon. Seemed to help. But I was very fluid except for the last 500m where I was just bloody tired. 15:01 ~ 3km, 5:00 pace per km. Till the next run friends, peace.