In an enthralling contest, Duns eventually secured a six rubbers to three win at home thanks to three deciding match tie-breaks in the final round of the tie.
The first round of matches immediately showed that it would be a tight affair throughout.
Duns' seconds, Suzanne Dixon and Nick Shaw, overcame Hilary Jackson and Lewis Armstrong in their mixed doubles match, but only thanks to a first to 10 point match tie-break, after St Boswells had squared the rubber at one set all.
In the women's doubles first round match, St Boswells' Lynn Bruce and Lucy Tile came from 0-3 down in the first set to beat Helen Forbes and Liz Dixon 7-5 6-4 in yet another close match.
Meanwhile, Duns' James Collin and William Dixon beat opposite numbers Adam Drummond and Matt Tile 6-0 6-2 in what was a close match, although not reflected in the scoreline.
In the second round of matches, St Boswells' number one mixed doubles pair of Drummond and Bruce stormed to a 6-1 6-2 victory over their counterparts Collin and Forbes.
Suzanne Dixon and Liz Dixon against Tile and Jackson also went to a match tie-break after finishing one set all. But, it was the Duns pair that won 11-9, in the second of what was eventually to become six match tie-breaks
In the men's doubles tie, Tile and Armstrong recovered from a thumping second set tie-break defeat against Shaw and Dixon to win the deciding match tie-break 10-2, to take the rubber and square the match at three rubbers each.
With the final round of matches set up perfectly for a thrilling finale, the players did not disappoint.
The first match to finish was the women's doubles between Duns' Forbes and Suzanne Dixon and opponents Bruce and Jackson.
Having taken the first set 6-2, the visitors had looked the favourites to take the rubber, but Forbes and Dixon fought back to win the second set 7-5 and take the tie to yet another deciding match tie-break.
After taking a solid lead in the decider, the Duns pair found themselves pegged back, but managed to come through 10-8 in the end.
With Duns needing just one more win to take the title, and St Boswells needing to win both the other matches on court, the pressure was on.
Having lost the first set 6-4, Drummond and Armstrong fought back against Collin and Shaw to take the second set to a tie-break, having failed to take set points at 5-4 up.
Despite that setback, the St Boswells pair fought hard to take the tie-break, and force the game into a match tie-break.
With both pairings fighting tooth and nail for every point, victory never looked out of sight for either of them, until Duns eventually captured a three point lead at 9-6 and a vicious forehand from Shaw up the line wrapped up the rubber, and the match.
Almost simultaneously, the remaining mixed doubles match, between the Tiles and Liz Dixon and William Dixon, also finished in a match tie-break.
After the St Boswells husband and wife pairing had taken the first set 6-3, the two Dixons recovered to square the tie 7-5 in the second.
In the closest match tie-break of the day, the home pair found luck on their side at 10-9 up, when a net cord tipped the ball over onto the St Boswells side for an 11-9 victory.
It has been a successful season for both sides this year, with Duns securing the women's first division league title, on countback, over St Boswells.