It was the first time since 1994 that Alexandra had won the competition and coach Tony Sanders said winning it in a jubilee year made it that much better.
''It was fantastic,'' Sanders said.
''They did bloody well. We kept our heads and kept our structure and we kept playing for 80 minutes.''
Alexandra put pressure on the home side right from the kickoff and Maniototo made mistakes that led to points.
Rory Campbell opened the scoring for Alexandra with a long range penalty before winger Sam Malcolm capitalised on a Maniototo mistake near its own line to run over untouched for a 10-0 lead.
Maniototo No8 Sam Pringle got his side back into the match with a try from close range but Alexandra continued to make most of the play.
Its physical rush defence saw centre Simon Lloyd force a mistake from his opposite, gather the ball and run 30m to score.
Campbell added a second penalty and a conversion, and Maniototo first five Charlie Hore kicked a penalty for a 20-8 halftime score.
As expected, Maniototo got back into the match after halftime and it was the impact of replacement No8 Josh Beer that was the biggest factor.
He made several telling runs and, after fullback Quinton Smith scored, he finished a nifty move where he fed the ball to a scrum close to the line, took a pass from Pringle and smashed over.
Hore could have given his side a two point lead with a relatively easy conversion but it sailed left, much to his disgust.
At 20-20, the match was anyone's, but Alexandra looked hungrier and continued to defend with gusto, stifling three or four Maniototo scoring chances in the final minutes.
With five minutes left to play, Alexandra was awarded a penalty 35m out and Campbell stepped up to calmly slot the goal.
Sanders said the play of his forward pack and the control by first five eighth Bevan Passmore were key in the win.
''He [Passmore] was fantastic.''
Alexandra will play Clutha this weekend in the countrywide final in Alexandra.
Central Otago
The final
Alexandra 23
Sam Malcolm, Simon Lloyd tries; Rory Campbell 2 con, 3 pen
Maniototo 20
Sam Pringle, Quinton Smith, Josh Beer tries; Charlie Hore con, pen
Halftime: Alexandra 20-8.
