Oratia would have scored first from a header if not for a tight offside call, while left wing Stephen Misselbrook looked likely to scorch the defence with his speed at any moment.
The ledger was level in the 37th minute after Steve Doherty was left with far too much time to dribble near the edge of the box, with the visitors taking the lead early in the second half due, in large part, to a pace advantage.
From there, the home side deteriorated along with the weather. Some nice one touch, overlapping football and dogged determination up front from the typically stoic Jack McNab aside, City were played out of the contest.
The normally clinical McNab, who is easily his side's leading goal scorer so far this season, missed a chance in each half that he would normally expect to finish, and might be wearing down slightly under the burden of being the side's sole threat up front.
The match was decided in the 83rd minute after a howling error from the home side's goalkeeper, who gently passed the ball to the feet of the striker who then beat him on the dribble.
From there, the frustration set in as conditions worsened.
The visitors hit the bar twice in the closing stages and could easily have scored two or three more goals.
Worst of all was the sight of one City player resorting to shoulder charges, pushing and then whooping while firing a throw-in deliberately at an opposition player in the dying stages.
