Whakarewarewa came flying back in the second forty, scoring four tries - including a brace to playmaker Te Rangi Fraser - but missed a couple of kicks that would have earned another bonus point.
Goal kicking alone kept Mount Maunganui in the contest against a surging Greerton Marist side that is peaking nicely.
The competition leaders were outscored five tries to two and had only the wayward goal kicking of the home side to thank for keeping them close.
Tries to Andrew Boyd, Tyrone Lefau, Joe Tupe, Leroy van Dam and George De Cottee were the result of Marist's desire to move the ball, and also ensured the Mount failed to pick up any competition points.
The Mount were affected by injuries in the build-up, and also lost Chris Croasdale to a broken fibula (sustained the play after scoring a fine try) and had no answer to the attacking raids led by Lefau, Nemani and van Dam.
The result had huge ramifications for the playoff race, with Te Puke Sports again taking the top spot following their five-point effort against an improving Te Puna.
The Mount slip to second, with Tauranga Sports leap-frogging Whakarewarewa into third with their bonus point win.
Marist have brought themselves back to the doorstep of the top four with four rounds remaining, and are in a dog fight with Whakarewarewa for the final play-off spot.
Whakarewarewa has a tough draw with matches left against Te Puna, Te Puke Sports, Rangiuru and Mount Maunganui, with Marist left to face Opotiki, Rangataua, Te Puna and Tauranga Sports.
The race at the other end of the table, assumed over a month ago with Rangiuru struggling to gain traction, may not in fact be done.
Opotiki helped themselves with a narrow 14-12 win over Rotoiti but Rangiuru, who have drawn with Rotoiti, beaten Greerton Marist, scored 28 points in a loss to Opotiki and snuck past Rangataua in the last four weeks, are suddenly an outside chance of staying up in the premier division.
Successive wins would be needed, beginning with next week's away date with Tauranga Sports.
