It was one-way traffic early as Counties Manukau took a 10-0 lead inside the opening 12 minutes.
However, Waikato worked their way into the contest well and began to string phases together and attack the Counties Manukau defence. While that defence was at times sketchy, Waikato weren't helping themselves as their handling let them down and they were at times isolated at the breakdown.
It took a brilliant run from McWhannell for them to finally break through, and they soon levelled the scores.
Counties had a great opportunity to hit the lead again before halftime but couldn't make the most of it, opting for scrums over penalty goals deep inside Waikato territory and being unable to score tries from them.
However, a rather wild sequence in broken play saw them take the lead through halfback Roigard, who scored off the back of flashy pass from Sotutu, who had collected an attempted kick and chase from Nanai-Seturo.
However, Counties Manukau's issues at the lineout proved to be the difference. All match, the hosts struggled to secure ball from their own throw, blowing several attacking opportunities and turning ball over in their own territory.
After Waikato reserve prop Norris hit back, scoring despite a subpar lineout from his own team, Waikato reserve halfback Xavier Roe swooped onto a wayward Counties Manukau throw at the back of the set piece and zoomed away to score.
With the hooter having sounded, Counties Manukau had a chance to attack deep from their own half, but when the ball hit the ground and Mosese Dawai toed it through for a late try, they lost the bonus point as well.
Waikato 34 (Laghlan McWhannell, Ollie Norris, Xavier Roe, Mosese Dawai tries; Damian McKenzie 4 cons, 2 pens)
Counties Manukau 20 (Zuriel Togiatama, Cam Roigard tries; Riley Hohepa 2 cons, 2 pens)
HT: 10-10