Waikato's array of young talent has shown a willingness to attack at every opportunity this season under first-year head coach Sean Botherway, and their aggression paid dividends against the more structured, static Southland.
Both sides conceded 50 points in their last hitout, but a mix of improved defence and wet conditions kept the scoreline in check in what was an enterprising clash.
A dangerous runner with ball in hand, McKenzie also demonstrated his precise kicking game, smartly evaluating the conditions early by playing for territory and turning around the Southland backline with deft kicks in behind the defence.
As the rain slowed, McKenzie turned to attacking the line, looking to provide inside balls and free his backline and he also utilised his speed to create several try-scoring opportunities.
Where Waikato were sound in the first half, Southland were sloppy, with poor handling in the wet as a result of some tough deliveries from the base of scrums and rucks.
A perfect chance to get on the scoreboard was blown when Tim Boys dropped it cold on an overlap with the line in his sights, with Southland managing only six first-half points from their rare forays into the Waikato half.
The leading points scorer in the competition, McKenzie's break kick-started the only try of the first half, with Declan O'Donnell capitalising on a kick which caused Southland confusion to score and give Waikato a slender 13-6 lead at the break. And Weber showed he is no slouch himself, picking up a stray pass to race nearly 40m to the line for his fourth try of the season.
After a slow first half, Lima Sopoaga's class shone through in the second, with a perfect cross-kick finding Keanu Kahukura before tries to the impressive Dillan Haloholo and Kieran Moffat made for a nervy final period for the hosts.
With Donald getting a run in the final 10 minutes, Waikato held on, McKenzie slotting a clutch penalty to cap off a fantastic night.
Waikato 30 (B. Weber, D. Collier, D. O'Donnell tries; D. McKenzie 3 cons, 3 pens) Southland 25 (D. Haloholo, K. Moffat, K. Kahukura tries; L. Sopoaga 2 cons, 2 pens). Halftime: 13-6.
