Cray Valley PM from Eltham in South East London are fourth in the South Eastern Counties League Premier Division with 15 wins from 23 games and - like Willand - are through to FA Vase last eight for the first time after trailing at home on Saturday.
The Millers beat Abbey Rangers 3-1.
Mid-Devon side Willand - who twice trailed to Deeping Rangers in the first half - won through thanks to a 77th minute Dean Stamp winner.
Stamp kept his cool in freezing conditions to fire home after a superb defence-splitting through ball from Brett Worbey.
Playmaker Worbey and Angus Wilson levelled in the first half.
The complexion and momentum of the fifth round tie turned on a brilliant off-the-line header by Ryan Guppy at the start of the second half, followed by Rovers having an effort cleared off the line before Stamp’s well-taken winner.
Saturday's Silver Street attendance 776
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