Te Puke did it tough minus their flanker but still led 6-5 after a forgettable, error-strewn first half that yielded two penalties through the sweet right boot of Simon Rolleston against a well-taken try to Mount wing Sam Hughes after a perfect cross-field kick from halfback Troye Elvin.
But it was evident the longer the undermanned home side stayed in the clash the more frustrated Mount became, with the side from up the coast not boosting their cause by kicking out on the full a couple of times then failing to find the sideline from a penalty.
It was Chisholm who fittingly ramjacked open the floodgates in the 55th minute when he burrowed over and Te Puke bagged their bonus-point try when Gideon Uelese dived over in the corner, with the game abandoned several minutes early following another minor flare-up.
In between, Te Puke took complete control, with No 8 Ryan Lambert and flanker Luke Perrott outstanding in Hinaki's absence, Lambert's initial dab setting up Chisholm and Perrott making the break that led to a try out wide to replacement wing Reece Spee on debut.
Spee's score lifted Te Puke to an 18-5 lead - close enough for Mount to claw their way back until an intercept from fullback Sipa Moimoi and 50m streak to the tryline.
"That was the one that broke them," said Chisholm, "and you could visibly see their heads drop. I don't care who you are, once that happens it's bloody hard to come back."
Chisholm basked in the win in his 150th game. The fact it was against Mount doubled his delight, although a similar result in the top-of-the-table clash with Tauranga Sports this weekend would surely please him as much or more.
He debuted in 2001, missing most of last season and all of 2008 when he was in the Waikato, and didn't expect to emerge without a few fresh wounds to add to his collection from Saturday.
"I've just been reminded again I'm still an ugly prick, but you expect it. It's always a big clash between the clubs and we knew they'd come at us hard. But hey, it's Saturday - you go to war for 80 minutes then have a beer together afterwards. After a win like that and a pretty cool milestone I wouldn't be anywhere else."
That Te Puke put 26 unanswered points on Mount in the second half a man down should be a worrying sign for the other Baywide hopefuls, especially given they lost wing Fred Ourabah (shoulder) in the first five minutes and had rep players Nick McCashin, Jack Wilson and Solomon King unavailable.
Te Puke could lose, and the first half on Saturday from both teams once the red mist cleared certainly wasn't one for the highlights reel. But it'll take a decent performance to topple them.
"Having never played for another club I know what it's like here, so if we lose and come off the field having worked our [butts] off for each other then so be it," Chisholm said. "But as long as we've busted butt then hopefully the wins keep coming. We've got momentum and want to keep it."
Tauranga Sports' 60-15 thrashing of Whakarewarewa makes this weekend's Domain clash mouthwatering.
Whaka, runners up in last year's Baywide, are in dire straits, winless after five weeks. Tauranga Sport have a firm grip on second place behind Te Puke, with their forwards in dominant form, laying the foundation for an eight-tries-to-two rout.
Rotoiti and Te Puna share third after winning - Rotoiti narrowly beating Waikite 20-10 and Te Puna outmuscling Rangataua 32-7 at home.
In a surprise upset Greerton Marist beat Opotiki at home in a 42-37 thriller.
Meanwhile, Rangiuru move to the top of the table in division one after beating Paroa 27-17 at their new Centennial park home ground in Te Puke. Te Teko had a narrow win over Whakatane Marist 17-13, Ngongotaha thrashed Ruatoki 47-8, Kahukura beat Reporoa 38-10 and Poroporo narrowly beat Marist St Michael's 17-15.