There were plenty of thrills and spills in the headline Formula 1 races, with the day being categorised as delightful or disastrous, depending on your point of view.
Hamilton's Nick Cole had been leading the series on his Kawasaki, but suffered engine troubles and had to use a back-up bike, finishing sixth and fifth in his two races to drop behind Charlett by three points in the standings.
Australian Linden Magee (BMW 1000RR) crashed spectacularly soon after the start of the opening F1 race, which forced proceedings to be stopped.
He was not seriously injured but his bike was a mess.
Wellington Suzuki rider Sloan Frost, who had been second overall on the table, crashed just a handful of laps after the restart.
The casualties kept mounting at Feilding. Suzuki ace Craig Shirriffs was forced to give up his lead and pull out of Race One when the bracket holding his brakes in place came loose.
At the beginning of Race Two, Taupo's Scott Moir (Suzuki GSX-R1000) had to withdraw when his bike suffered a malfunction on the start line, which dropped him back to fifth in the standings.
New Plymouth's Hayden Fitzgerald (Suzuki GSX-R1000) could sympathise as he had electrical problems and also pulled out, leaving him seventh in the class standings.
Frost won Race Two from the also-returning Shirriffs, with Charlett third.
But because the Cantabrian Charlett had avoided any dramas it really was his day.
"My Suzuki GSX-R1000 performed brilliantly," he said.
"To win this series for a second year in a row would be great, and I'm not taking anything for granted because there's still a round to go.
"But, regardless of how it all works out for the Suzuki Series, it has still been great in terms for getting myself set up for the national championships [starting January]. I feel like I'm in a good position."
Despite having surrendered his series lead to Charlett, Cole remains optimistic.
"It is still a pretty close competition. I'm just glad that the back-up bike, straight out of the crate from the factory, is a very good machine. Bring it on at Wanganui, I say.
"I have a very good chance of winning the series there, looking at my past results on the Cemetery Circuit, and I'm feeling confident."
But Frost, now 11 points back in third, said he may not race at Wanganui next week.
"There's not a lot of point in me risking myself for a series I can't now win. I've got to think about the nationals coming up.
"It has been a mixed day for me, a DNF and a win. It's frustrating because if you drop one out of six races, you really haven't got a chance."d