Nairn produced an excellent performance at Station Park to hand Buckie their heaviest league defeat since November 2019.
Goals from Andrew MacLeod, Ben Barron and Harry Hennem gave the home side a comprehensive victory against an out of sorts Jags side.
Manager Graeme Stewart brought in Lyall Keir for Josh Peters up front, with captain Sam Pugh returning in place of Jack MacIver in midfield.
Horace Ormsby missed a superb chance to put Nairn ahead early on, firing over an empty net from 10 yards after Calum Mackay drew Euan Storrier and squared it for the Nairn winger.
Mackay also came close on 15 minutes when he latched onto a pass from Ormsby, but his low shot from 12 yards hit the base of the post with Storrier beaten.
At the other end Lyall Keir headed straight at the keeper at the back post from Scott Adams’ cross, with his team mates appealing for a foul on Max Barry in the middle.
Andrew MacLeod put Nairn deservedly in front on 26 minutes, finding space on the edge of the area and curling a tremendous shot beyond Storrier into the top left corner of the net.
Ben Barron then broke clear and drilled in a low strike that was well saved by the legs of Storrier.
Play was halted for a 15-minute spell after a spectator took ill and was attended to by the medical staff from both teams.
Jags should have been level ten minutes before the break when Keir robbed Ross Tokely and bore down on goal, but he shot wide of the right post from 15 yards.
The visitors were enjoying their best spell of the match and came close again just before half time, Jack Murray set up well on the edge of the box, but his left foot drive flew just past the right hand post.
Adams missed a superb chance when he volleyed wide from close range after a great header across goal from Cohen Ramsay.
There was still time in an action-packed fist half for Barron to burst into the left of the penalty area, and draw another fine save from Storrier with a powerful drive.
Thistle made an attacking change at the break, Josh Peters coming on for Dale Wood.
Barron put the home side two in front on the hour mark, Ormsby racing clear on the left flank and playing it across for the County number nine to convert at the far post.
Liam Harvey, Jack MacIver, Marcus Goodall and Hamish Munro were all brought off the bench to try and change the game for the toiling Jags.
Home goalkeeper Dylan MacLean flapped a MacIver corner just wide of his own post with 14 minutes remaining.
Nairn sealed the win in the 89th minute, Storrier’s clearance deflected into the path of Hennem, who finished expertly from 30 yards into the bottom right corner to send the home fans into raptures.
A rare league defeat for Buckie, who were simply second best on the day. Manager Stewart describing it as “our worst performance for three years”.
The Jags will need to bounce back quickly with a Quarter Final Aberdeenshire Cup tie against local rivals Deveronvale up next on Tuesday night.
Buckie Thistle: E. Storrier; J. McCabe (H. Munro 75) S. Morrison, J. Murray, C. Ramsay (M. Goodall 63) ; S. Pugh (c), D. Wood (J. Peters 46); A. MacAskill (J. MacIver 63), M. Barry, S. Adams (L. Harvey 63), L. Keir. Sub not used: D. Strong, L. Mackinnon