A collapse in the tail, losing four wickets in the last three overs, wasn't concerning according to Mitchell.
"We knew we only had a couple of overs [left], so tried to rotate the strike a bit and have a crack at anything - at that stage every run counts."
After losing the early wicket of Amy Foreman for a duck, the home side gained good momentum through a 79-run partnership between Monique Rees and powerful hitter Melanie Megan.
Former White Ferns captain Aimee Watkins opened up, racing to 47 off 35 deliveries, including five boundaries, to seal victory.
Watkin with her spinners was the pick of the Wanganui bowlers (1-14 off seven overs), while newcomer Eden Stone (1-37) also looked promising.
Mitchell said there was a lot of positives to take from the match, while making 181 is a huge improvement on the bad old days of three years ago when Taranaki would bowl Wanganui out for 33 runs.
"We've really grown as a team since then, are seeing good numbers to trainings and have a great culture developing.
"This is the first game of the season and only a stepping stone.
"Last season, we pulled out our best performance against Wairarapa and if we can improve on today, we've got a good chance at taking them again next Sunday.
"We had three new players out there today - one who hasn't played for 17 years, one who hasn't played for 10 and one who's Year 13 at high school making her first foray into the women's league, so they'll only grow in confidence as the season progresses."
Raj was also pleased with the match.
"We couldn't ask for more in terms of effort and team camaraderie, Wanganui kept fighting until the end.
"We've taken a few work-ons from this match - boundary hitting in the last five overs, consistency with our bowling and making catches stick while fielding - but it's a really positive start to the season."