Peter McMahon and KS Genoa. © Nichol Taylor
It was heart-stopping stuff as 25 of the best combinations from both sides of the Tasman did their best in front of thousands to grab a share of the $750,000 prize pool and conquer the Leopoldo Palacios designed course - one of the biggest ever seen in New Zealand.
Only two went clear in the first round - and both were Australian. Rising young star Jamie Winning on Vangelo Des Hazelles and McMahon.
Last year's winner Katie McVean and Dunstan Forest II dropped a rail as did Robert Steele and Gospel.
Twelve combinations went through to the second round. Clears were a little more prolific this time, with Samantha McIntosh and the stunning chestnut Selle Francais stallion Lindberg des Hayettes joined by three Australian combinations.
McMahon was the last to go and while he rubbed one fence, nothing fell, giving him victory. The winner's cheque for the 27-year-old former diesel mechanic-turned professional rider is $150,000.
McMahon, who had to have reconstructive surgery on his collarbone after breaking it in the practice arena at the 2008 Olympics, paid tribute to his wife Michelle Lang-McMahon, herself a former world championship rider.
KS Genoa is schooled on a lunge rein and walker, with McMahon only getting on for a couple of practice fences before going into the arena.
"She's best that way," he said of the sometimes rather difficult mare.
KS Genoa, a 14-year-old Hanoverian by Graf Landau, has had several foals by embryo transfer, and is the dam of the 10-year-old eventer Pearly Gates.
"It was a big relief for Pete to win," said Michelle Lang-McMahon.
"More than the money it was just so rewarding after his disappointment at the Olympics. He nearly hung up his boots after that. It was the most amazing show, apart from a World Games or Olympics it is the best show either Pete or I had ever been to, a real credit to New Zealand," she said.
Palacios, the 2008 Olympic course designer, built one of the toughest courses ever seen in New Zealand. "It looked OK but then when we walked the lines I thought this will take some jumping. It was tough," said McMahon.
BBC equestrian commentator Michael Tucker said the course and the money on offer was setting new standards around the world.
"Leopoldo knows the world standard and he set a course worthy of the money and most definitely one of the biggest courses seen here," he said.
"His course today showed the ones who keep cool under pressure and the horses with scope."
• New Zealand continued its domination of the tri nations, winning the final day and taking the leg. The New Zealand team to compete in South Africa in the second leg next month is Robert Steele, Maurice Beatson, Ike Unsworth and Simon Wilson.
Today wrapped up six very full days of competition at one of the largest sporting events in the Southern Hemisphere.
NZ Speed Horse of the Year: Anna Stephen (Martinborough) Constantine 1, Wendy Schaeffer (Australia) Koyuna Sun Storm 2, Jacqui Wright (Taukau) Cheekie Boy 3, Bridget Hansen (Havelock North) Monamie NZPH 4, Oliver Edgecombe (Waipukurau) Apollo van Evendael 5, Edward Bullock (Pukekohe) Wesserwolf Tane 6.
Premier stakes one star: Katie McVean (Mystery Creek) Dunstan Delphi 1, Becky Allen (Australia) RSB Jacana 2, Maurice Beatson (Dannevirke) Kiwi Relic 3, Melanie Purcell (Whakatane) Billistic 4, Catherine Cameron (Cambridge) Kahurangi Tardak 5, Sue Thompson-Brown (Hastings) Air Hill Myka 6.
Tri nations, final round: New Zealand 1, South Africa 2, Japan 3. Final: New Zealand 1, South Africa 2, Japan 3.
New Zealand team to compete in South Africa: Robert Steele (Hawera), Simon Wilson (Waipukurau), Maurice Beatson (Dannevirke), Ike Unsworth (Tauranga).
Three day event three star: Jonathan Paget (Muriwai) Clifton Promise 1, Anne-Marie Styles (Papakura) As You Like It 2, Anne-Marie Styles (Papakura) Opera Groove 3, Kate Wood (Northland) Easy Tiger 3.
Polocrosse, Domhealth Polocrosse Challenge Trophy, day one: NZu21 17, President's Selection 9. Day two: President's Selection 18 NZu21 9. Accumulated points: President's Selection 27, NZu21 26.