McKenzie made no mistake from right in front, adding the extras to make it 10-0 as the hosts were rewarded for piling into breakdowns in greater numbers than their Bay of Plenty counterparts.
The Steamers struck back with an unconverted try to fullback Byron McGuigan soon after following a wonderful turnover on halfway from halfback Jono Kitto.
The ball went right through the hands of Nic Evemy and Bardoul before Tino Nemani chopped off his right foot - and possibly behind one of his own players - to put McGuigan over untouched.
Pivot Dan Hollinshead missed the conversion after earlier pulling a penalty wide from a handy position, making it 10-5 midway through the opening half.
An arm wrestle developed, with the Steamers winning an attacking lineout following an early disengagement from a midfield scrum. Some scrappy play led to a five metre scrum just before the break, but the Steamers' attempt to push a Waikato scrum featuring Super Rugby props Ben Tameifuna and Josh Hohneck around ended with number eight Carl Axtens under pressure and, one phase later, another penalty against the Bay for entering a ruck on the angle.
The second half started in messy fashion, with both sides pushing passes and spilling ball in the pursuit of quick points.
The first points of the half came in comical fashion following a floated pass in midfield from Steamers captain Culum Retallick.
New Zealand under-20s hooker Hame Faiva swooped on the mistake, snatching the ball before it reached his opposite Joe Royal before galloping 30 metres to score in the tackle of two desperate covering Steamers.
Sadly the promising youngster suffered a lower leg injury in scoring and would take no further part in proceedings.
The conversion made it 17-5 to Waikato, forcing the Bay to chase the game over a final 20 minutes that threatened at times to border on a farce.
Evemy split the game open with 15 minutes to play, slicing through the Waikato midfield before feeding a surging Siaosi Iongi, who in turn found McGuigan for his second try of the night.
Hollinshead added the extras to make it 17-12, but the Steamers could not apply any pressure on the restart.
Waikato had one try disallowed for a player cleaning out past the ball, but the respite for the Bay was short-lived.
All Blacks Sevens flyer Declan O'Donnell crossed in the righthand corner with 10 to play, and when McKenzie added the extras from the chalk the lead had been extended back out to 12 points.
The Steamers lay siege to the Waikato line in the closing stages but could not dot down to place the hosts under any real pressure.
The Bay conceded 30 turnovers in total, which, when combined with Waikato's 23, made for an average game of football at this level.
A last minute try to Waikato replacement Jordan Payne pushed the score out to 29-12, consigning the Steamers to the unwaited distinction of being the first team to finish last in the premiership and championship competitions in successive seasons.
Waikato (Brad Weber, Hame Faiva, Declan O'Donnell, Jordan Payne tries; Damian McKenzie 3 cons, pen) Bay of Plenty (Byron McGuigan 2 tries; Dan Hollinshead con) HT: 10-5.
