Having already crossed for the Cherry and Whites' second try in the second half, Twelvetrees stepped forward to clinch a late win. With Freddie Burns already off the pitch, it was his midfield partner who was on the money from the tee after the pack had earnt a penalty from a scrum on halfway.
With Rob Cook another candidate to step up to the pressure and convert the penalty, Twelvetrees explained it was his responsibility to end an afternoon of high-drama and secure his side's first Aviva Premiership victory of the season.
"To be honest with you I didn't even look at Cooky.
"Sav (Tom Savage) was off the pitch so I was captain, and I just thought I'd step up and do it - I love those opportunities and that's why we practice goal-kicking so hard in the week.
"Luckily for me I was able to put it over, to get the win for the boys: we deserved it."
With Northampton's late sucker-punch score, it appeared as if the hunt for the first win would continue up to Newcastle but Twelvetrees insisted the heads in the Gloucester camp didn't drop and the game wasn't quite over until the final whistle blew.
"Under our posts with 20 seconds to go, we just said 'let's get the ball back'.
"We knew if we did that we would have a chance of winning it, whether that would be with a chance for a try or whatever.
"That chance came, the forwards were immense and luckily I kicked it over.
"I'm just delighted for the boys - we really needed that."
The start of the season was full of promise but a disappointing duo of opening results left a deflated feel in the camp and Saturday's win was just the result to kick start the campaign.
"There's a lot of self-belief in this team, we had a lot of frustrations from the two weeks before.
"So we just wanted to get out and play rugby, and not say 'what if'.
"We played some good stuff, and we could have had the game closed out far earlier if we're honest.
"That self-belief rose up again, we dug deep and we refused to let the game slip away."