Despite the significance of the game and the impressive run of form coach Ron Cane is playing down the match and wants the team to solely focus on "getting the three points".
"Nothing changes. We have to approach this game the same as we have we every other in this competition," he said.
"We need the three points first and foremost. I'm not trying to make it into a big game because I don't want players to suffer in the build up.
"They have worked very hard and have the right to win that title if they get the winning result, but they need to keep calm and focused.
"We can't be complacent. Otumoetai won't just roll over and they will want to end their season on a high too."
Cane, in his first season coaching, said "patience, concentration and team work" would be key to victory.
"The team is very strong in every area. We work from a solid defence, have excellent creativity in midfield and lethal strikers," he said.
"So it is our game to lose. We can't take our foot off the gas and just expect a result.
"There has definitely been a shift in the team recently. I don't think they had belief at the start of the season but now we are playing with confidence.
"I just hope they can finish it off. This could be the highlight of their careers - something to really cherish. It means a lot and we are nearly there."
United have one remaining Premier League game against second placed Northern United after this weekend.
The WaiBOP Premier League Division 1 winners will contest a playoff match to qualify for the Northern League premier women's competition, based out of Auckland.
But Cane dismissed any speculation about United making it into the Northern League premier women's competition next season.
"I'm not thinking about that. I'm just looking at the three points on Sunday," he said.
"This season is very much a rebuilding stage for the club and we want to try and lay a platform for next year and years ahead.
"We can't get too far ahead of ourselves."
Rotorua United v Otumoetai Bay, Neil Hunt Park, 1.30pm kick-off.
