Groombridge was now suddenly on top of the standings, a solid 14 points ahead of new No2 man Draper, with Titirangi's Callan May (Yamaha YZ250X) elevated to third, eight points further back, and Macdonald forced down to fourth overall, just one point behind May, and the title was Groombridge's to lose.
A finish of fifth or better at Tokoroa on Sunday would be enough for Groombridge to win his first national enduro title and that's what he did, ending the day third overall, behind a fired-up Draper and Glen Eden's 2015 overall champion Chris Birch (KTM 250 XC-F).
"I knew where I had to finish and did enough to get the job done," said Groombridge.
Meanwhile, May finished the day fourth overall at Tokoroa and this was enough for him to snatch third overall for the enduro championship, ending 15 points behind Draper.
Macdonald battled all day on a borrowed bike at Tokoroa. He managed to finish fifth overall, but that wasn't quite enough to earn a place on the championship podium. It was a disappointing end to a season that had shown so much promise for the 17-year-old.
It was perhaps some consolation for Macdonald that he managed to still win the over-200cc two-stroke class.
"It took me a while to get used to the borrowed bike [on Sunday]," said Macdonald. "I crashed it too, so I guess it just wasn't my weekend. I'm still only 17, so I've still got a long way to go and I'll be back new year."