The 600cc supersport class also underwent a massive points reshuffle at the top with the series leader after round one, Rees' 21-year-old son Damon Rees, qualifying quickest at Teretonga on Saturday, but then crashing out of the weekend's first 600cc race.
This dropped him to 18 points behind his nearest challenger, Wainuiomata's Shane Richardson, and when Richardson then won the following day too, this opened the gap out to 26.5 points.
Meanwhile, another big mover at the weekend was Tauranga's Rob Gibson, who has jumped from third to first overall in the 250cc Production class.
Leaders remained unchanged in the other classes Invercargill's Jeremy Holmes (1000cc superstock class), Taumarunui's Leigh Tidman (Superlites), Christchurch's Andy McLaughlin (Lightweights), Christchurch's Dennis Charlett (Pro Twins), Christchurch's Matthew Hoogenboezem (125G), Ashburton's Paul Skinner (Senior Development class), Christchurch's Jackson Cotton (Junior Development class) and sidecars pair Spike Taylor (Masterton) and Robbie Shorter (Tauranga) settling in to defend their respective positions at the top when the series heads to the North Island next month.
With the series now at the halfway stage and the South Island phase of the competition put behind them, the riders now look ahead to round three at Taupo's Bruce McLaren Motorsport Park on February 25-26 and perhaps even more of the same drama that unfolded on the Teretonga circuit on this weekend just gone.
There are now just six more races to go for each class, at Taupo and at the finale at Hampton Downs on March 4-5, and anything could still be possible.
Class leaders after the second for four rounds of the nationals:
Superbikes: 1. Tony Rees (Whakatane, Honda) 131 points; 2. Alastair Hoogenboezem (Christchurch, Honda) 113; 3. Sloan Frost (Wellington, Suzuki) 105.
1000cc Superstock: 1. Jeremy Holmes (Invercargill, Honda) 152; 2. Chris Defiori (Te Kauwhata, Kawasaki) 56; 3. Rob Whittle (Raglan, Aprilia) 43.
600 Supersport: 1. Shane Richardson (Wainuiomata, Kawasaki) 137.5; 2. Damon Rees (Whakatane, Honda) 111; 3. Jake Lewis (Rangiora, Triumph) 102.
Superlites: 1. Leigh Tidman (Taumarunui, Yamaha) 112; 2. Gavin Veltmeyer (Auckland, Suzuki) 99; 3. Chris Defiori (Te Kauwhata, Yamaha) 93.
Lightweight: 1. Andy McLaughlin (Christchurch, KTM) 132; 2. Sam Goulter (Ashburton, Yamaha) 120.5; 3. Lewis Dray (Ashburton, Yamaha) 81.5.
250 Production: 1. Rob Gibson (Tauranga, Kawasaki) 116.5; 2. Campbell Grayling (Opunake, Kawasaki) 109.5; 3. James Squire (Timaru, Kawasaki) 94.
Pro Twins: 1. Dennis Charlett (Christchurch, Suzuki) 152; 2. Josh Augustine (Auckland, Suzuki) 102; 3. Jordan Burley (Hamilton, Suzuki) 88.
125GP: 1. Matthew Hoogenboezem (Christchurch, Honda) 136; 2. Chris Wallinger (Christchurch, Honda) 97; 3. Chris Cain (Auckland, Honda) 79.
Development class (Senior): 1. Paul Skinner (Ashburton, Kawasaki) 147; 2. Phillip Lowe (Hastings, Suzuki) 90; 3. Phil Denovan (Christchurch, Suzuki) 76.
Development class (Junior): 1. Jackson Cotton (Christchurch, Kawasaki) 152; 2. Luke Huddlestone (Christchurch, Aprilia) 105; 3. Joey Ransome (Ashley, Kawasaki) 101.
Sidecars: 1. Spike Taylor (Masterton) and Robbie Shorter (Tauranga) 152; 2. Peter Goodwin and Kendal Dunlop (Albany) 116; 3. Barry Smith and Tracey Bryan (Tauranga) 100.