Rangers came from behind to book a first ever place in the UCL Knockout Cup semi-finals.
Deeping were trailing at the break to the Division 1 leaders after a below-par display but boss Tuncay Korkmaz rallied his troops to produce a commanding second half performance to win 5-1.
Both teams struggled to get going on a heavy pitch but it was Oadby who threatened first, Stacey Cartwright blocking Levi Porter’s effort.
Deeping thought they had taken the lead when David Burton-Jones rounded goalkeeper Pickering and although Callum Earls got in a block the ball appeared to be over the line.
The visitors broke the deadlock in the 29th minute when Porter played in Courtney Meade and his curling shot found the top right hand corner.
The Poachers continued to threaten, Earls bringing a good save from Doughty, Meade having a shot blocked by Simon Ashton and the same player heading too high.
Oadby replaced the injured Porter with former Leicester City ace Julain Joachim for the second half but Rangers came out a different side.
Beck went close for Rangers before Meade missed a great chance for Oadby.
Deeping levelled just before the hour when a Scott Ginty corner was headed back into the mix by Ashton for Oliver to flick onto Beck to tap home from a yard out.
Rangers increased their lead on 71 minutes, another Ginty corner was inadvertently flicked on by a Oadby defender for Simon Ashton to head home.
Four minutes later Scott Bogusz played a one-two with Oliver before advancing and dinking over the goalkeeper.
It was 4-1 when Spencer Tinkler converted a penalty after Beck was tripped.
Beck beat the offside trap and set up Kev Gilbert for number five.
Deeping Rangers: Doughty, Flack, Parker, Tinkler, Cartwright (Bogusz - 21 mins), Burton-Jones (Cpt.) (Lewis - 82 mins), Gilbert, Ginty, 9. Oliver (Lewis - 88 mins), Ashton, Beck.