"I knew it would be like that," she gasped afterwards. "I knew it would be really tough and it come down to the last 10 metres, because it's been that close all season in every race.
"I felt good coming round the bend with 150 metres, which was good, because sometimes I feel like my legs are going, but I trusted my sprint."
Petty has led the way in middle-distance running over recent years, becoming New Zealand's second-fastest 800m exponent (1m 59.06s) when she took out the 2015 World University Games title.
At 25, she believes she still has plenty left to improve and her local summer campaign has been a warm-up to an off-season programme, based in Seattle under new coach Danny Mackey.
"My training is going well, but we're not really aiming to be super sharp yet. We want to running fast leading into world championships - that's the aim - so it's encouraging to running like I am now.
"Times didn't matter today, the main thing was to get the title, but it was always going to be tough."
While Camp has kept Petty honest this season - they are now 2-2 in head-to-head competition - that battle has nothing on the one within the Petty household, where husband Sam finished fourth in the men's event (1m 52.52s) at Hamilton and farm dog Tux runs rings around them.
"He's way faster than both of us - he can probably run a 1m 20s 800m, so he keeps us honest."
In that men's 800m final, Canterbury's Brad Mathas also stretched his string of titles to six in a row, easing away in 1m 50.66s.
Fellow Cantabrian Kelsey Berryman starred in the field, winning the women's long jump with 6.40m, which would have been a 10cm personal best, except for a strong tail wind. In sixth, Paralympian Anna Grimaldi's 5.58m was just four centimetres off the distance that earned her a gold medal at Rio de Janiero last year.
Pole vault prospect Olivia McTaggart of Auckland took out her second title of the weekend, clearing 4.20m in the U20 grade.
In the women's 100m hurdles, Cantabrian Fiona Morrison captured her fifth national crown with a swift 13.35s clocking, but national record-holder Rochelle Coster stole the show by tumbling over the penultimate hurdle in spectacular fashion and failing to finish.
After his 100m national record the previous evening, Joseph Millar cruised through the heats of the 200m in 21.86s, but will need to run a second faster to get near the resident mark over the half lap in Sunday's final.
NZherald.co.nz will live-stream the NZ track and field championships in Hamilton from 10am Sunday.
NZ Track & Field Championships
Porritt Stadium, Hamilton
Men
400m: Quin Hartley (Manawatu Wanganui) 48.63s 1, Thomas Smith (Hawkes Bay Gisborne) 49.09s 2, Michael Gutry (Waikato BOP) 49.38s 3.
800m: Brad Mathas (Canterbury) 1m 50.66s 1, Michael Dawson (Auckland) 1m 51.71s 2, Eric Speakman (Hawkes Bay Gisborne) 1m 52.21s 3.
100m Hurdles: Joshua Hawkins (Auckland) 14.31s 1, James Sandilands (Canterbury) 14.61s 2, Aaron Booth (Auckland) 15.68s 3.
4 x 100m relay: Waikato BOP 41.09s 1, Canterbury 42.38s 2, Auckland 42.43s 3.
Long Jump: Jesse Bryant (Canterbury) 7.22m 1, Brendon Barnett (Wellington) 7.06m 2, Liam Speer (Auckland) 6.96m 3.
Men U20
400m: Luke Mercieca (Auckland) 49.47s 1, Harry Symes (Manawatu Wanganui) 49.87s 2, Bailey Cotton (Tasman) 50.48s 3.
800m: Tom Moulai (Canterbury) 1m 53.56s 1, Josh Nairne (Wellington) 1m 53.58s 2, Liam Turner (Southland) 1m 54.59s 3.
110m hurdles: Kolone Alefosio (Samoa) 14.77s 1, Ben Kennedy (Auckland) 15.01s 2, Tom Gill (Canterbury) 15.11s 3,
4x100m: Wellington 43.34s 1, Canterbury 43.76s 2, Auckland 43.81s 3.
Shot Put: Ryan Ballantyne 19.12m (Waikato BOP) 1, Nick Palmer (Hawkes Bay Gisborne) 17.82m 2, Raiarii Thompson (Tahiti) 17.16m 3.
Pole Vault: James Steyn (Auckland) 4.45m 1, Ben Kennedy 4.25m 2, Sam Harris (Canterbury) 4.05m 3.
Javelin: Anton Schroder (Southland) 54.74m 1, James Tudor (Southland) 43.66m 2.
Men U18
400m: Michael Graham (Auckland) 50.81s 1, Sam Gouverneur (Otago) 51.12s 2, Sam King (Canterbury) 51.61s 3.
110m Hurdles: Olly Parkinson (Auckland) 14.34s 1, Joshua Shih (Auckland) 14.73s 2, Nic Forster (Canterbury) 14.93m 3.
4x100m: Auckland 42.23s 1, Canterbury 43.76s 2, Wellington 45.13s 3.
Hammer: Anthony Barmes (Auckland) 54.78m 1, Jordyn Hetaraka (Northland) 49.44m 2, Caleb Moore (Waikato BOP) 48.73m 3.
High Jump: Thomas Moloney (Auckland) 1.91m 1, Gerard Hickey (Wellington) 1.87m 2, Daniel Trenberth (Canterbury) 1.83m 3.
Triple Jump: Andrew Allan (Southland) 13.54m 1, Ryan Churchill (Tasman) 12.91m 2, Keiran Pete (Manawatu Wanganui) 12.46m 3.
Paralympic Men
Javelin: Rory McSweeney (Otago) 47.71m 1.
Women
400m: Megan Kikuchi (Auckland) 56.94s 1, Jamie Sowter (Auckland) 57.04s 2, Amy Robinson (Waikato BOP) 57.31s 3.
800m: Angela Petty (Canterbury) 2m 03.35s 1, Katherine Camp (Waikato BOP) 2m 03.54s 2, Ellen Schaef (Wellington Harriers) 2m 06.31s 3.
100m Hurdles: Fiona Morrison (Canterbury) 13.35s 1, Ashleigh Sando (Waikato BOP) 14.20s 2, Leanna Ryan (Waikato BOP) 14.64s 3.
Hammer: Nicole Bradley (Auckland) 56.41s 1, Lauren Bruce (Canterbury) 51.65m 2, Montaya Wharehinga (Wellington) 51.00m 3.
Javelin: Madeleine Chapman (Auckland) 50.98m 1, Tori Peeters (Otago) 50.82m 2, Laura Overton (Otago) 48.99m 3.
Long Jump: Kelsey Berryman (Canterbury) 6.40m 1, Mariah Ririnui (Waikato BOP) 6.24m 2, Corinna Minko (Australia) 6.08m 3.
Shot: Maddison Wesche (Auckland) 15.04m 1, Lauren Bruce (Canterbury) 13.03m 2, Emma Ryan (Southland) 10.85m 3.
Triple Jump: Atipa Mabonga (Southland) 12.35m 1, Ashleigh Bennett (Taranaki) 11.85m 2, Candice Richer (Tahiti) 11.22m 3.
Women U20
400m: Georgia Hulls (Hawkes Bay Gisborne) 55.87s 1, Amanda Fitisemanu (Tasman) 56.91s 2, Jessica Hood (Waikato BOP) 57/57s 3.
800m: Kelsey Forman (Wellington) 2n 14.31s 1, Harriet Bush (Canterbury) 2m 15.03s 2, Georgia Clode (Auckland) 2m 15.67s 3.
100m Hurdles: Summer Rutherford (Canterbury) 14.99s 1, Natasha Eady (Auckland) 15.44s 2, Ella Ransley (Waikato BOP) 15.55s 3.
4x100m: Auckland 48.91s 1, Waikato BOP 49.57s 2, Otago 49.74s 3.
Pole Vault: Olivia McTaggart (Auckland) 4.20m 1, Imogen Ayris (Auckland) 3.95m 2, Kazaya Vos (North Harbour Bays) 3.15m 3.
Hammer: Mellata Tatola (Auckland) 48.99m 1, Emma Wilson (Southland) 41.11m 2, Dyani Shepher-Oates (Southland) 38.44m 3.
Women U18
400m: Maia Broughton (Canterbury) 56.84s 1, Anna Hayward (Canterbury) 57.42s 2, Samantha Hardie (Tasman) 58.10s 3.
800m: Tessa Hunt (Wellington) 2m 13.77s 1, Lily Trotter (Canterbury) 2m 14.13s 2, Krystie Solomon (Waikato BOP) 2m 14.34s 3.
100m Hurdles: Kayla Goodwin (Waikato BOP) 14.37s 1, Cara Lonergan (Auckland) 14.71s 2, Tegan Duffy (Canterbury) 14.89s 3.
4x100m: Canterbury 49.08s 1, Manawatu-Wanganui 49.65s 2, Waikato BOP 49.84s 3.
Long Jump: Tegan Duffy (Canterbury) 5.71m 1, Kayla Goodwin (Waikato BOP) 5.65m 2, Genna Maples (Manawatu Wanganui) 5.54m 3.
Discus: Tatiana Kaumoana (Waikato BOP) 45.78m 1, Mellata Tatola (Auckland) 41.37m 2, Caitlin Bonne (Canterbury) 41.33m 3.
Shot Put: Mellata Tatola (Auckland) 14.43m 1, Jaidyn Busch (Canterbury) 14.41m 2, Kaia Tupu-South (Auckland) 14.13m 3.