After a four-year affiliation with her horse, Robertson said they had developed a relationship that transcended a mechanical rider/mount existence come the pressures of showjumping time.
Ngahiwi Cisco, on who she won the Dunstan Horse Feeds Young Rider of the Year crown here last March, is her only entry in the premier Olympic Cup event on Sunday.
"It's a big class before the Olympic Cup so it's a big build-up class so people who do well tend to do well in Olympics but time will tell if that happens.
"It eases a few nerves because it certainly helps to know the horse goes out and is jumping well."
She won't compete in today's Ultra Mox Lady Rider of the Year but will defend her Young Rider crown tomorrow.
"I just decided to give him a day off."
Yesterday Robertson went into the event with a modicum of self assurance that she had a chance to win but also mindful one could never be overly confident with horses.
"They can be great levellers. You can be on the top of the world one day and the next you're in the back paddock."
It was a blemish-free clear for Robertson and Cisco as seven of the 30 original combinations came back for the against-the-clock jump off.
The winning combo were second off rank, setting the pace and tempo with tight turns and a title-defining stride into the last leg in 51.65 seconds.
Not surprisingly the remaining combinations had to push the envelope but found themselves dancing with the devil and fatally flirting with the rails.
"I was second to go so it was just a waiting game from then on," said a beaming Robertson.
With seven in the jump-off mix, Robertson said there was always the chance one combination would come away without a ribbon "so it was a gamble to put my foot down and go a bit faster but, yeah, it paid off."
Te Awamutu teenager Emily Hayward-Morgan must have given Robertson a few palpitations but she erred on the last, incurring four faults in 48.56 to settle for runner-up on her mount, AP Ninja.
Rio Olympics eventing hopeful Clarke Johnstone, of Matangi, was third on Quainton Labyrinth accruing four faults in 50.61.
It helped Robertson's cause that Ngahiwi Cisco enjoys the cooler climes that prevailed at the Hawke's Bay Showgrounds yesterday.
"He enjoys jumping in the cold and he goes better on the heavier ground after all that rain we've had."
She saluted the course that Werner Deeg, of Germany, designed.
"It was technical, booked to height and we had a nice lead-in fence to the rest of the course, which is what you'd expect coming into the Horse of the Year each year."
Robertson is sitting below Hayward-Morgan on the national Young Rider of the Year Series leaderboard so yesterday's victory added to her sense of satisfaction.
"She's a little way ahead [on points] and I'm not going to go to some of the shows at the end of the season although it's nice to do well in the season."
Her mother was watching but her father was at work in Christchurch.
Her best friend, Lily Catterick, is grooming for her to maintain a camp of familiarity.
"She's wonderful and looking after the horses really well so it's great to have her here."
Robertson thanked her sponsors - Cadalleria Toscana, Beta Vet and Mitavite.
Gisborne cousins Fraser Tombleson and Jenny Randall took the quinella in the AHD Ltd 6-year-old Horse of the Year Championship after an exciting jump off.
In dressage, Vanessa Way, of Taranaki, has had a strong start to her Hoy Show, with wins in three classes.
The country's marquee showjumping extravaganza will continue throughout the week, culminating with the Olympic Cup on Sunday.
More than 1400 riders are competing across 14 disciplines.
Day 1 results:
Showjumping, Norwood Gold Cup: Olivia Robertson (Christchurch) Ngahiwi Cisco 1, Emily Hayward-Morgan (Te Awamutu) AP Ninja 2, Clarke Johnstone (Matangi) Quainton Labyrinth 3, Oliver Edgecombe (Waipukurau) Ultra Blue NZPH 4, Georgia Massie (Dannevirke) Larinium LS 5, Maurice Beatson (Dannevirke) Conyers 6.
GJ Gardner pro-amateur rider of the year championship: Amanda Roy (Gore) Rumours NZPH 1, Zoe Shore (Ashburton) Zara 2, Helen Kippen (Ocean Beach) Velocity NZPH 3, Tayla Mason (Wellington) Silverstar 4, Heather Pease (Piopio) Llannation 5, Sally Clark (Dannevirke) Victoria's Secret 6.
AHD Ltd 6-year-old horse of the year championship: Fraser Tombleson (Gisborne) Mea I 1, Jenny Randall (Gisborne) Nero Bello 2, Bernard Denton (Feilding) Horsesports Sequell 3, Tegan Fitzsimon (Canterbury) Corlinka 4, Amanda Wilson (Hikurangi) Woodbine Legacy ST 5, Claire Wilson (Waipukurau) McMillan's Chuck 6.
Dressage, HOY level 1 horse 1C: Karla Tarr (Orakei), Kinnordy Ravel 1; Amanda Berridge (Cambridge) Glamorgan By Design 2, Henrike Seifert (Gisborne) Gurteens Tyra 3, Anna Williams (Hastings) Tuahu Gemma 4, Elisha Wade (Waipawa) Donneregal 5, Jane Olsson (Christchurch) Astek Georgia 6.
Level 2 musical freestyle: Vanessa Way (Taranaki) NSC Pronto 1, Debbie Barke (Rotorua) RM Limbo 2, Holly Leach (Hamilton) HP Fresco 3, Nicky Pope (Auckland) HPH Phelix Phelicious 4, Alix Campbell (Albany) Astek Robina 5, Rebecca Rowlands (Canterbury) Solo 6.
Harrison Lane level 3 musical freestyle: Vanessa Way (Taranaki) NRM Andreas 1, Laura Saamu (Auckland) Astek Rhapsody 2, Melissa Galloway (Marlborough) Windermere J Obei W 3, Kathryn Corry (Te Kuiti) Boom Chica Boom 4, Kim Whitelegg (Albany) Vollrath Fuerst Patrick 5, Lucy Robertshawe (Waipawa) Salute 6.
Hansen Products level 5: Victoria Hewson (Tauranga) Arife F 1, Sophie de Clifford (Opiki) Ashanti 2, Tessa Van Bruggen (Blenheim) Fortunato 3, Sharlene Royal (North Shore) New World Frankie J 4, Tracy Smith (Hamilton) Lord Louis 5, Janelle Sangster-Ward (Marlborough) Dunstan Astek Ghisella 6.
Level 4 horse: Vanessa Way, NRM KH Arion 1, Sharlene Royal (North Shore) Sonic Spirit 2, Mihi Shepherd (Whangarei) Hot Chocolate MH 3, Jutta Rosenblatt (Wanganui) Vollrath Lauretta 4, Christine Weal (Te Awamutu) Stoneylea Lord Locksely 5, Jennifer Sim (Karaka) Stoneylea Lancelot 6.
Today's events:
Premier Arena, Arena A:
* 8am-11.30am: Show hunter.
* 11.30am -1.30pm Sport horse
Arena B:
* 8am -1.10pm: 2* eventing dressage
* 10.30am-1.10pm: 3* eventing dressage.
* Class 18(b), 2pm-3.30pm: Lady Rider of the Year 1.35m - 1.45m.
* Class 19, 4pm- 5.30pm Horse 1.35m.
NRM Arena:
* Class 18(a), 8.30am -10.30am: Lady Rider of the Year 1.35m - 1.45m
* Class 20, 11am-1.30pm: Junior rider.
* Class 21, 2pm-6pm: Horse 1.25m.
Arena Two:
* Class 22, 8.30am-10am: Pony 1.25m.
* Class 23, 11am-5pm: Horse 1.15m.
Arena Three:
* Class 24, 8am-1.20pm: Pony 1.05m.
* Class 25, 1.30pm-3.50pm: Pony 1.15m.
