Niamh Briggs’ side were beaten 33-10 to England in their opening match in Parma but showed signs of encouragement in the closing stages against hosts Italy, scoring two late tries as they ate in to a 17-point deficit before eventually going down 24-17.
Finishing well has been a common theme throughout Ireland's campaign but wing Barrett is now challenging her side to come flying out the blocks against a Scotland side who are also winless in their first two outings.
"Everyone's really excited for this last game," she said.
"Against Italy, we really showed that we can fight right until the end and so against Scotland we want to bring the fight from start to finish.
"We've really worked on our shape and we've made some really good line breaks so it's all about building on that now.
"Scotland are a really good side and they had a great match against France, especially with a strong first half. We all know they are a tough team and we equally need to come out strong.
"We're super excited to get into this last match but at the same time don't want it to end and would definitely like to play a few more."
Barrett first picked up a rugby ball at Erris Rugby Club aged 11 and honed her skills as part of the Ballina girls' team.
She soon caught the eye and received her first senior international call-up in 2023, making her debut against Colombia in WXV3 last autumn.
"I started playing rugby when I was 11 with a close friend but there was no girls team, so we played with the boys for about a year," she said.
"Then one of the coaches said that I should more to another club, which was about an hour away, but it was an all-girls team. I played most of my underage rugby there.
"I always played Gaelic football but rugby has really taken over in recent years."
Ireland head coach Briggs has made seven changes to her side that lost to Italy, with vice-captain Kate Flannery starting at fly-half and Robyn O’Connor reverting to full-back.
And Barrett, who now plays club at UL Bohemian RFC alongside Flannery, believes that the team's history of friendships has been the key to their most memorable moments in the inaugural Summer Series.
"I now play club with a lot of girls on the team,” she said.
"That really helps us play well together on the pitch and I'm always excited to get out there.
"I played for Ireland U18's with a lot of the girls which is great, because it shows how we've all come through that pathway together and are now able to continue playing at international level as a team."
