Down six points with six minutes remaining, Aho, who also scored Waimate’s opener, sidestepped and powered his way through four defenders to score under the posts on Saturday afternoon.
The result means that after two rounds Celtic and Temuka are the only teams unbeaten in the race for the Hamersley Cup, with Celtic set to be tested in the next round by a wounded Harlequins, and Temuka by a resurgent Old Boys.
Running downhill to start, MacKenzie looked in the box seat for much of the first half.
They conceded in the 26th minute as a shower swept across the ground and Aho swept around a stretched 14-man defence, but other than that, the visitors made the running.
Openside Josh Brosnahan opened the scoring in the eighth minute, fullback George Williams was over in the 20th, and on halftime wing George Folau showed the high ball skills of Wallaby Israel Folau to catch and offload a bomb to an open Josh Morton for the third.
The halftime huddle put a firecracker up Waimate, who started the second half with authority.
With No 8 Loni Toumohuni breaking tackles and dishing offloads the score was 15-15 inside 10 minutes.
The Rams kept their heads, though, and their forwards found a way back into the match. No side looked dominant and things got quite scrappy as the substitutes came on but when the Rams won a penalty the goal-kicking that had deserted Williams in the first half came good.
When he nailed a penalty from halfway to give the Rams a 21-15 lead in the 74th minute it was going to take something special from Waimate to win it.
As it turned out they retrieved the kickoff and Aho did the rest.
Waimate 31 Mackenzie 7