The visitors arrived at Wilderness Lane with a two-point advantage at the top of the table but with the Magpies nipping at their heels after an incredible winning streak of 18 matches.
Spixworth scored a goal in either half, the second coming after the hosts were reduced to 10 men just eight minutes after the break, to settle an epic title tussle in front of an impressive crowd of almost 900 spectators.
Visiting manager Andrew Collison was without 28-goal top scorer Luke Tuttle through injury and had his heart in his mouth eight minutes in when Harleston playmaker Scott Roberts curled a shot just wide from 25 yards.
Spixworth keeper Nathan Pauling was in the thick of the action, being forced to head clear in the 17th minute but only managing as far as Nicky Howell, who lobbed the visiting number one, only for Joe Easton to be in the right place to head off the line.
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Pauling proved the difference within four minutes though, as Harleston were building momentum, when Connor Delaney burst behind the Spixworth defence from the left and struck a sweet right-footed shot towards the top-right corner only to see the keeper superbly tip the ball around his post.
It proved pivotal as the leaders took the lead 13 minutes later, when Easton's shot from the edge of the box was deflected and squeezed through Billy Johnson's gloves. The linesman initially ruled out the goal but, after some confused looks, referee Andrew Tyne over-ruled the decision.
Harleston centre-back Matt Howard was booked for a late tackle on Matt Doyle just before the goal and then unwisely earned his second in the 53rd minute, with an unnecessary, late sliding tackle on Karl Horton.
The feisty second half, featuring six yellow cards, was settled in the 70th minute when the strapping chest of centre-forward Paul Cook diverted the ball into the path of Doyle and the winger's first touch took him into the box to allow him to curl into the bottom-right corner to seal the success.
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston: Johnson; O Willis, Howard, Furlong, Burke; Howell (C), S Willis, Roberts, Page, Delaney (Blyth 67); N Russell. Unused subs: Hitch, C Russell
Spixworth: Pauling; Halliday, Easton, Barrowclough, Cross; Morgan, Page, Owen, Horton, Doyle (Woodgate 79); Cook (C – Terrington 72). Unused: Cushing
Attendance: 875
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
Harleston v Spixworth (blue) in the Anglian Combination Premier Division final. Spixworth celebrate their win. Picture: ANTONY KELLY (Image: archant 2017)
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