But Opotiki were able to add to two tries of their own in the 15th and 23rd minutes to left winger Michael Webber. Opotiki first-five Greg Smith could only convert one of the tries to level the score.
The turning point for Opotiki was the loss of their captain Dean Elmiger who limped off while his side was on attack.
However Acton soon had his side back in the lead with Cunningham putting the rangy No 8 through a gap in Opotiki's defensive line. With 30m to the posts, Acton showed why he was given a Steamers jersey when he stepped the fullback and cantered to score under the post for Cunningham to convert to take the lead to 19-12 before halftime.
After the break the home side racked up their bonus point try, when lock turned fullback MaNasa Bole touched down inside the first five minutes of the second half to increase the lead 24-12.
Rotoiti coach Kevin Lee's experiment of trying Bole at fullback would have failed miserably if they had been playing a better side, Bole was constantly found out of position and the side were lucky Opotiki were unable to capitalise.
The visitors managed to narrow the margin in the seventh minute when Smith kicked a 30m penalty and the side scored their third try against play when centre Hamuera Hudson intercepted a pass and dashed 55m to score. Smith converted the try to take the score to 24-22.
Opotiki only have themselves to blame with poor option-taking and an equally poor kicking game - the side missed three penalties in the dying minutes of the match to win.
Acton said he was proud of how his side turned around their fortunes from last week.
"It was the same as last year, it was two points last year and just like last week, another physical game. I'm stoked to finally get a win and things are looking up, from last week anyway."
The captain said he was impressed with the work ethic put in by Joshua White who was a demon on defence.
"He's a good young fulla ... I think he's gone through the Bay age groups. He had a good one. He's real fit and that helps some of us more unfit guys to have him around."
Result: Rotoiti 24 (Beau Kiel 2, Jesse Acton, MaNasa Bole tries; Whakataki Cunningham 2 cons) Opotiki 22 (Michael Webber 2, Hamuera Hudson tries; Greg Smith 2 cons, 1 pen). Halftime: 19-12.