With Rees a non-finisher, it means Richardson has taken maximum advantage and he now tops the standings, a huge 18 points ahead of Rees.
There are two more 600cc races scheduled for tomorrow.
"It was a good race, all in all," said the 21-year-old Richardson afterwards.
"It was a shame to learn that Damo (Rees) had gone down, but that's racing. I didn't realise he'd crashed until afterwards. I had no pit-board signals and I was just keeping my head down.
"I'm happy to get another win but it's still a long way to go in the championship yet."
Meanwhile, it was also shake-up time in the glamour superbike class, with defending champion and early 2017 series leader Sloan Frost beaten into second place by his main threat for the title, Whakatane's Tony Rees (the 49-year-old father of Damon).
Frost had qualified fastest and earned one valuable point for that achievement, but it was Rees who gained most when he collected 25 points for the race win.
Frost's championship advantage has now been shaved from 10 points to just six.
This class also looks forward to two more races tomorrow.
There were fresh winners in several of the other classes today with Whangaparaoa's Nathan Jane winning the sole Superlites race, Ashburton's Sam Goulter winning today's race in the Lightweight class and Timaru's James Squire winning the day's sole 250 Production class outing.
After the Teretonga round this weekend, the riders head north for round three at Bruce McLaren Motorsport Park, Taupo, on February 25-26, and then the finale at Hampton Downs, near Meremere, on March 4-5.