With Ben Jordan sin-binned for a professional foul and Mike Foulstone’s try and Harry Cople’s conversion opening the scoring for Celtic it looked like being a difficult afternoon for the Knights.
However, they were 30-6 ahead before Celtic next scored, through Billy Yarrow, on 67 minutes.
Connor Wilson and Joe Crossland nipped over to help establish a 12-6 interval lead, Charlie Barker landing the first two of his six goals.
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In the second half Luke Camplin, Joe Millward and Crossland dotted down, Barker and Jake Tyson crossing after Yarrow’s effort.
Knights now go on to the Conference play-offs when they will meet Underbank Rangers at home this Saturday.
Eastmoor Dragons missed out on the play-offs after losing 23-12 to Hunslet Warriors in a Cross League match.
The Dragons have finished third in League E, despite taking the lead through Alfie Goddard, Jamie Deal improving.
Declan Nicholson scored their other try with Deal again goaling.