But despite three golden chances to score tries in the second half, they just could not put a plucky Taihape away, who switched to a short lineout to nullify Thornbury, kick-chased at every opportunity and swiftly spread the ball to each sideline to outrun Border's bigger pack.
Putting bodies on the line, prop Ritchie Iorns fought for every inch, as did No8 Tremaine Gilbert, who was knocked senseless inside the first ten minutes but managed to convince referee Ben Lourie to let him stay on the field, something flanker Timi Teepa could not do after being helped off following a series of kamikaze tackles.
First-five Tom Wells, who had kicked brilliantly all match, had a chance to win the game by making a fifth successful goal inside the last two minutes with a 40m penalty attempt.
But he just struck the lower left-hand post - ironically almost the exact spot where Border's final kick missed in last year's final to deny them the title.
Wells and Dane Whale both pressured young Border reserve fullback Grayson Tihema, who rushed on after only seven minutes as again key-man Nick Harding could not overcome his hamstring injury, limping off shortly after kicking the opening points.
First-five James Forsythe took over that role and almost nearly grabbed a first half intercept try before slipping short, while his drop goal attempt with five minutes left to take Border outside of kicking range just drifted to the right.
Border should have already been safe after lightning centre Kaveni Dabonaise broke through near halfway and dashed away from his chasers, but with his 21st try in sight the young man raised an arm to celebrate and Wells' desperate diving ankle-tap lowered him 2m short of the line.
Having survived Wells' final kick, Border managed to turnover possession twice from Taihape in injury time, with hooker Cole Baldwin ripping the ball loose for halfback Lindsay Horrocks to boot it into the stands.
Having sat and chanted beside each other in packed northern lower grandstand, there were tears flowing from both club's supporters - joy from the relieved Border and heartache for Taihape.
Williams acknowledged both team's deserved to win, having sweated on Wells' final kick.
"But [there was also] Kaveni's [miss], you know.
"What a stoic bit of defence 40 minutes into the wind.
"I'm just so rapt for them, because I know how long they worked for it, and the people in the grandstand, I know how long they've waited. And I feel for Taihape."
He praised captain Fraser Middleton for his composure in the second half, while believing Stark was "best on show".
For Taihape coach Kerry Whale, he could not have asked for more from the team he has spent four years building up by hand.
"I'm really proud. Finals come down to single moments - a missed kick at goal and then a charge down - that's it."
He felt Iorns, Teepa, and Gilbert had led a forward pack who gave it everything they had.
Border created an early chance as Harding attacked with winger Tom Symes down the touchline, leading to a 35m penalty chance which Harding hit low but accurate for 3-0 in three minutes.
But the hobbled fullback was soon signalling to the sideline, around the same time Gilbert was guided off but then refused to go to the bench when told by Lourie it would be a permanent substitution.
Wells and Dane Whale immediately started the grubber and chip kicks at Tihema, who snaffled them, but one of his attacking clearances saw Dabonaise a half-step in front, letting Wells tie the scores after 14 minutes.
Tuimauga carved off big metres with every hit up to put Border on attack, with Thornbury rolling over the line after a drive from the lineout, only to be ruled a double-movement by Lourie.
But with Taihape unable to secure their lineouts against Thornbury, Border were back on attack and Tuimauga went low to brush the chalk for 10-3.
Taihape kept up the kicks and pressure, then an Iorns charge was carried on by Wells before halfback James Barrett nearly slipped through, then Dane Whale cleverly reached over the tryline ruck to ground the ball for 10-10.
Feeling it now, Taihape worked forward but were met with tacklers determined to put them out of action, while Stark and flanker Jake Alabaster hunted turnovers.
Whale tried the drop kick and only the tallest player on the field could have reached it, which Thornbury did with a head start to win the race against Taihape lock Hamish Bennett and dive over underneath the other posts.
But Border soon had to face playing the period around halftime with 14 men after Symes was sinbinned for taking Taihape winger Glen Horton's legs out from under him when going for a bomb.
They still had a late chance for two barge-overs from corner lineouts, but the smaller Taihape pack got low and drove them out for a big lift at halftime.
Baldwin nearly scored early when a Taihape spill was hacked to the line, yet winger Jaye Flaws arrived to grapple with him right over the chalk.
Border stayed on attack and Tuimauga just lost control when barging over again, before Taihape used the breeze for booming clearances.
A midfield turnover and Border infringement led to Wells getting a 35m penalty in front, then minutes later Border were penalised again from 52m out, Wells having second-five Luke Whale take the longer kick, which was well away.
After Dabonaise was tripped when celebrating early, Border were penalised, with Taihape tapping quickly and Gilbert nearly getting away on a big run back up the field.
Again Border were caught offside midfield and Wells was cool as ever with the long range penalty for 17-16 with 13 minutes left.
Two exhausted teams threw everything at each other in the final ten minutes, with Forsythe just missing the drop goal and Wells striking timber with his penalty attempt, in a heart-stopping conclusion to a great game of rugby.
Waverley Harvesting Border 17 (Tietie Tuimauga, Gavin Thornbury tries; Nick Harding pen, James Forsythe 2 con) bt PGG Wrightson/Ballance Taihape 16 (Dane Whale try; Tom Wells 3 pen, con). HT: 17-10.