Renshaw scored an unbeaten 89 off 52 balls as Australia posted a total of 196-5 before the tourists restricted the Tigers to 189-6 to seal a win and an unassailable 2-0 lead in a three-match series.
The 30-year-old has a torrid run with the bat in tour, notching up scores of 4, 2, 0, 0 and 18 in previous four innings which includes the ODI series that the Aussies lost 2-1.
Renshaw has not been a consistent member of Australia's squads in all three formats but was happy to contribute to an important victory.
He said after the game: "I think obviously my international career has been a bit strange around different formats, but I think just being able to be comfortable in my skin, today was a really important innings for me.
"It came just after a run of low scores, just remembering why I wanted to play and how I wanted to play. The way that I started was one of the best starts that I've had in my (T20) career.
"And I was really pumped about that, and then to go on and make the score that I did and set the team up for a good win was really good in this format.
"I think there's always those doubts around whether you're good enough, especially when you're in and out of formats and in and out of teams. So it was nice to realise that I'm good enough at this format."
A part-time offspinner, Renshaw has also still managed to be Australia's most prolific wicket-taker on tour with eight scalps.
"Apparently my bowling's not great. I saw a little titbit from one of the Bangladeshi players," he quipped. "I see my bowling as something that I love doing, but I see it from more of a batting point of view, trying to work out what the batter's trying to do each different ball.
"I know that I'm probably not going to hit every ball where I want to, so trying to just adjust where I can with fields, and just do whatever I can for the team. And fortunately, I've got a couple of wickets this tour."
Matt Renshaw struck a career-best 89 not out from 52 balls to help Australia beat Bangladesh by seven runs in the second T20I as the visitors took an unassailable 2-0 lead in the three-match series.
Joel Davies starred with the ball on international debut to help Australia beat Bangladesh by four wickets in the first of three T20Is in Chattogram on Wednesday.
Australia veteran spinner Nathan Lyon is confident he will be ready for the Test series at home against Bangladesh in August as he continues his recovery from what he describes as a "traumatic" injury.
Cooper Connolly produced the finest innings of his international career to drag Australia to a thrilling one-wicket victory over Bangladesh in the third ODI in Mirpur, preventing a series whitewash despite a remarkable late collapse.
