The match opened up significantly in the second half as the visitors pressed forward, which in turn gifted Otumoetai's speed merchants on the flanks opportunities going forward.
Plenty of silky one touch passing led to a penalty corner with 10 minutes to play, which was expertly converted by Toby Harris to seal the result.
Coach Aaron Buchanan, who slipped on for an eye-catching stint with three minutes to play, said his players were "stoked" to have reached their first final in about a decade.
"Having a home semifinal and final is what we were aiming for and we've done it - it makes it much easier for the boys to prepare," Buchanan said.
"It was a tough game, I think we didn't play as well as we could, so there is plenty of work to do next week."
Buchanan believed his side's strong structured approach and crisp passing meant they were every chance in the final, and he did not have any preference on who they would meet.
"We're not bothered - a final's a final. Whoever turns up, it will be tough."
CMS Mount, which beat Otumoetai 4-0 in pool play, will be that side after beating the Pukekohe Indians 4-2 away from home.
Bayleys Otumoetai 2 (Cory Bruin, Toby Harris) Kohekohe 0