Fortune favoured the brave as the Cadets fielders dropped both batsmen on one and the Mount ended up with a highly competitive total of 263/8.
Cadets entered the fray with a positive mindset, but the Mount bowlers grabbed a couple of cheap wickets at the top of the innings.
New Zealand under-19 representative Joe Carter (66) and BOP rep Scott Steward (48) got their side back on track but with the Mount needing an outright win to claim the first piece of Baywide silverware for the season, Cadets looked likely to be bowled out.
However, James Birchall and Morgan Bidois batted out the last 13 overs with Cadets finishing on 182/8, which meant Greerton had to fall chasing down East Bay United's target to give the Mount the title.
So to Pemberton Park, where home side Greerton went out to bat confident of reaching what looked to be a relatively modest target of 156.
However East Bay United stalwart Steven Ford simply wrecked the home side chances of winning the Baywide trophy with a heroic man-of-the-match performance.
Earlier he batted for 48 overs to top score with 43 and then he wreaked havoc on the Greerton top order.
In his first four overs Ford took three wickets without conceding a run and finished with the best figures of the innings of 5/28, as Greerton were dismissed for 105 to end their title hopes.
Tailender Tommy Clout made 29 not out with Dean Butterworth taking 3/23 and Mark Berry 2/19.
Mount captain Mark Divehall went through a hugely contrasting day of emotions, from abject despair as he and his fellow top order slumped to a seemingly impossible position of 95-7, before the remarkable, record-breaking fight back and the news Greerton had fallen at the final hurdle to give Mount Maunganui the silverware.
"We lost the toss and Cadets started really well, bowled in good areas and we weren't patient enough,"said Divehall.
"We played some lazy cricket and were in a spot of bother before Alex and Tony came in. Alex counter-attacked from the start, using his feet to their slower bowlers and medium pacers, and got some momentum going for us.
"Tony hung around and didn't hit a shot in anger for a while, and we got on top of them a little bit mentally, as I think they were a bit surprised at the fightback from the two guys, who put on 144, which I am pretty sure is quite comfortably a club record for the eighth wicket.
"It was impressive to get to 263/8 after being 95/7 and we declared after Alex got his 100, and we thought 52 overs would be enough.
"We started really well with the ball, and Tony [Goodin] being the Bay's premier bowler and making his debut for ND this year, bowled exceptionally well and took 3/27 off 14 overs.
"We took seven catches behind the wicket, which is really good, and testimony to where we were putting the ball.
"Joe Carter was outstanding for them, and didn't look like getting out until Tony got him, but some credit should go to Morgan Bidois batting at 10, who hung around with James Birchall in the ninth wicket partnership for around 13 overs to shut us down.
"We heard during drinks that Greerton had been rolled but we took it with a grain of salt until it took a phone call from [BOP Cricket media manager] Barry Leabourn to confirm the final result."
The Mount now play a semi-final of the Northern Districts club championship against the top Hamilton club side, with a chance to play off for the title of the best club in the Northern Districts region.
Meanwhile at the Te Puke Domain, two centuries took centre stage in the match between Te Puke and BOP Indians.
BOP rep Bharat Popli anchored his side's total of 189, with a chanceless 110, while Te Puke skipper Tai Bridgeman-Raison led from the front with an unbeaten 107 as the home side cruised to an eight wicket win.
Central finished the Baywide Cup with a hard fought win, in a low-scoring encounter against Tauranga Boys' College at Smallbone Park in Rotorua.
Tauranga Boys' were removed for just 135 but Central lost seven wickets on the way to victory.
Baywide Cup results, December 15:
East Bay United 155 (Steven Ford 43; S Sidhu 3/9, Tommy Clout 3/23) defeated Eves Realty Greerton 105 (T Clout 29no, Matt Earl 24; S Ford 5/28, Dean Butterworth 3/23, Mark Berry 2/19)
BOP Indians 189 (Bharat Popli 110; Sean Gibson 5/31, Charles Williams 3/34, Matt Dwight 2/28) lost to Te Puke 190/2 (Tai Bridgeman-Raison 107no, Steven Crossan 37)
Tauranga Boys College 135 (Mark Orchard 30; Jason Trembath 4/40, Ben Watkinson 2/18, Ben Blackett 2/26, Andrew Gibbs 2/28) lost to Central 136/7 (Julian Danby 66; Tom MacRury 2/15, M Orchard 2/34)
Mount Maunganui 263/8 (Alex Gooding 103, Tony Goodin 63; James Birchall 2/26) winning draw from Element IMF Cadets 182/8 (Joe Carter 64, Scott Steward 48; T Goodin 3/27, Daniel Hill 2/39)
Points Table (Final): Mount Maunganui 86, Te Puke 81, Greerton 80, East Bay United 77, Central 75, Cadets 69, Tauranga Boys College 58, BOP Indians 52.