Boro were being held 1-1 by lowly Beaconsfield when Gale brought on Nick Dembele, Matt Paterson and Luke Hallett on 75 minutes.
The first two provided fresh attacking options while Hallett replaced Josh Huggins in central midfield.
The changes paid off as Paterson set up Dembele to curl a delightful winner from outside the penalty area into the top corner and send Boro level on points with second-placed Hayes & Yeading.
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‘As I told the team afterwards, sometimes it (the substitutions) pay off, sometimes they don’t. This time we got our rewards, on another day we draw 1-1 and it’s two points dropped.
‘It was important to win, but we shouldn’t be putting ourselves in that position.
‘We could have been a few goals up in the first half. We don’t score enough goals, I get that, and we missed some good chances.
‘We dominated the first half but then we let them back in it in the second half.’
Defender Ryan Woodford had put the hosts into a 15th minute lead the Beaconsfield levelling just after the hour mark through Nathan Minhas.
Dembele’s great winner, though, ensured Gosport picked up a ninth league win in 14 fixtures.
And after beating fifth-bottom Beaconsfield, next up at Privett Park next Saturday are third-bottom Merthyr followed by rock-bottom Kings Langley the following Wednesday.
‘I know people will see these as winnable games,’ said Gale. ‘But every game is winnable - you’ve just to got to go out and win them.
‘Merthyr are in a false position and Kings Langley will be tough - top, middle or bottom, all the games are tough. No-one is going to give you the points, you have to earn them.’
Gale had taken Hallett, on loan from Forest Green, and ex-Pompey youngster Harvey Rew out of the starting line-up against Beaconsfield.
Theo Lewis, after recovering from a hamstring injury, returned to the starting line-up.
‘The Southern League is an unforgiving, physical league,’ explained Gale. ‘Luke and Harry have been excellent - they’ve exceeded my expectations - but before this season they’d only played Academy football, not men’s football.
‘I’ve no qualms about playing the youngsters but there is also a time to take them out and use your senior players.
‘Luke had been looking a bit leggy. He trained with us Thursday, he trained with Forest Green the following day, and I thought he looked fresh when he came on.
‘I explained the situation to Luke and Harvey - next Saturday is another game.’
Gale will certainly have to make changes against Merthyr as centre half Woodford starts a suspension for his red card in the fiery FA Trophy exit to Salisbury, and midfielder Theo Widdrington has been recalled by Hawks.
Gosport could make a new midfield signing before Merthyr’s visit, but Mike Carter is not expected to be recalled from his loan spell at AFC Portchester where he has started the last three Wessex Premier League games.
‘I trust Dave Carter (Portchester boss) to do what’s best for the player,’ said Gale. ‘Carts is desperate to play but I’ll only bring him back when he’s at the level where he can affect games for us. He’s not quite there at the moment.’
Managing players’ game time is key for Gale, who was pleased to see Lewis return to league action at the weekend. ‘If we can keep Theo fit we’ll have a hell of a player,’ he remarked. ‘That’s the key - can we keep players fit?
‘Theo did well for 70 minutes (against Beaconsfield) but I have to manage him - and that was enough for him there.’