Chinnor were knocked off the top when they lost 10-6 at home to derby rivals Aylesbury in dreadful conditions at their exposed Kingsey Road ground.
The omens were not good for the home side when they were penalised for a scrummage offence on halfway after Aylesbury's initial kick-off had gone dead.
Full back Winterburn landed the downwind penalty for Aylesbury, who had former England veteran Gary Pearce in the front row.
Against the wind, Chinnor pressed the Aylesbury line, but could not break through.
At the other end, the visitors captalised when Chinnor spilled the ball and Gent scored in the corner. Winterburn's excellent conversion made it 10-0.
This advantage seemed insufficient when Chinnor fly half Conor Begley landed two penalty goals early in the second half.
But he missed an easier kick and Chinnor's tactics of ignoring further penalty attempts and going for a try floundered against a well-organised Aylesbury defence.
This result ended a six-match winning streak for Chinnor, who had Paul Fincken sin-binned along with Aylesbury's Winterburn in the first half.
Witney lost their crucial game away to fellow strugglers Olney by the slimmest of margins a penalty goal just ten minutes from full time.
In difficult conditons, Olney started well, even though Witney skipper Paul Thomas opted to play with the elements in the first period.
Thomas missed a tricky penalty attempt, while flanker Will Worrall's darting run down the blindside ended with a dropped pass.
Witney, in fact, played better against the elements, but Thomas's two further shots at goal fell short of the posts.
With both sides pushing for the winning points, Olney broke clear. Witney No 8 Martin Lyall came in to make a try-saving tackle, but was then penalised for not rolling away quickly enough.
The penalty was awarded ten metres in front of Witney's posts and Olney's kicker did not miss.
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