Mustangs made it 5-0 when "Jeff the Magician" Yacap blasted the ball between the outfield for a big home run.
"That was an amazing win," coach Ron Hollis said.
"Only one error for our boys today. We worked on a few little things during the week and the boys put it into play today."
Mustangs have a home game on Saturday playing a strong Bluesox team.
"Nice to see softball being played back here (in Whanganui)," Hollis said.
Meanwhile, in the Manawatu senior men's premier league, Ezi Finance Wanganui Braves lost 9-2 to last year's champions Huia Chiefs on season debut.
The Braves outfit has a new pitching roster, with local chucker Shaun Terry coming from Feilding Raiders, and Linton Army thrower Dazz Dalton.
Terry started on the mound, and as expected was a little rusty pitching his first game of the season. But he did take six strikeouts in the four inning affair.
The new mercy rule was applied when the Chiefs had a seven run lead and notably struck out arguably the Manawatu region's top batter in Wayne Norman three times.
Dazz Dalton pitched the last inning before the game was called. He will be a good asset to the team as he can play most positions and bats well as seen on Saturday when he got a safe hit off Manawatu's best pitcher Kelly Dyason.
Highlight of the day was a huge home run by Carl Priddle in the bottom of the second, scoring Glen Casey in the process, who had hit safely to centre right field.