Matt Paterson came off the bench to grab the winner a minute from the end of normal time - while he also had a stoppage-time penalty saved - as Boro ran out 2-1 winners in Gloucestershire.
Harvey Rew headed Gosport - who finished the campaign in ninth position in the table - ahead right on the stroke of half-time.
But following Olly Mehew's leveller after the restart the spoils looked set to be shared, then substitute Paterson struck after being introduced to seal all three points on the final-day for Boro.
‘I can't fault anyone. We picked up a couple of injuries, Matt Paterson came on and got us the winning goal, Aston Leigh came on and did well. Billie Busari came on for 10 minutes and did really well,’ said boss Gale.
‘It was one of those, all hands to the pump, but a good way to finish. It's always nice to finish with a win.
‘I do feel we've got a really good group of players, we just need to add a bit more quality to it, we need to make sure we keep our better players on the pitch more than they have been (this season).’
Gale was forced to switch systems to a back three following the withdrawal of defender Ryan Woodford through illness while Busari was only fit enough to feature off the bench as he still struggles with an ankle issue.
However, Gosport adapted well to the late formation change, taking a lead into half-time after Rew headed home Rory Williams' cross late in the first-half.
But Boro were dealt a blow when Mehew was on hand to make it 1-1 to set up an enthralling final 25 minutes. Gosport had nothing riding on the game having already missed out on the play-offs, but kept pushing for a winner up until the last.
And they were rewarded when Paterson reacted quickest to fire home after fellow substitute Aston Leigh's initial effort had been parried on 86 minutes.
When another substitute, Busari, was brought down and a penalty was awarded in stoppage-time, it appeared as though Gosport's victory margin would be even great. But Yate stopper kept out Paterson's spot-kick as it ended 2-1 to the visitors.
