The striker entered the fray alongside Jamie O'Hara after 70 minutes with the scoreline still goalless and Pompey's 4-1-4-1 system proving a tough nut to crack.
Just over 10 minutes later though and it was 2-0 with Darren making the crucial breakthrough via a close-range header before setting up the second for Jamie to side-foot home.
"Patience - I think that was the word today - keep playing, keep believing, organise, concentrate and then sooner or later everybody knows we will have the chance to score goals," reflected Gus.
"There were too many players behind the ball but Benty opened up the whole situation.
"He made a big impact and that shows how important sometimes the subs are, players don’t realise how important they are even when they are sitting on the bench because you can go on and change the game. He did fantastic but that is what you need to show."
Meanwhile, Gus was quick to state the importance of keeping a clean sheet - not least when Juande Ramos took off a defender when making the substitutions and committing ourselves to winning the game.
"That was the key because when you play in these kind of games sometimes you start going a little bit crazy going forward, you may leave a little bit of space for the opposition and then maybe on the break or from set-play they score a goal," he added. "After that it's too difficult to come back so the clean sheet was the key to the win."
Gus Poyet praised the team's patience in finally breaking down Pompey on Saturday - with Darren Bent taking the plaudits.