The former Olympian, World Champs representative and World Cup final competitor had the luxury of being the last of a trio of riders to go in the jump-off.
Twelve started the class, but just Beatson, former World Cup series winner Simon Wilson on Swinger and Tess Williams on her flea-bitten grey Craighaven Nitro progressed through to the second round.
Both Williams and Wilson had a rail each in the jump-off, with Beatson slightly slower but still clean and clear.
Both Gollywog and Swinger are veterans of the showjumping world, at 16 and 17 years respectively. Defending NZ series champion Katie McVean was rapt with her fourth placing aboard Dunstan Zasjany D in their first World Cup start. She was also fifth on Dunstan Daffodil.
Beatson's World Cup win rounded off a brilliant show for him - he also won the horse grand prix aboard Schimmel Warrior.
Bomac World Cup (opening round of the NZ series): Maurice Beatson (Dannevirke) My Gollywog 1, Simon Wilson (Waipukurau) Swinger 2, Tess Williams (Gisborne) Alltech Craighaven Nitro 3, Katie McVean (Mystery Creek) Dunstan Zasjany D 4, Katie McVean (Mystery Creek) Dunstan Daffodil 5, Sally Steiner (Tauranga) Wickliffe Brannigan 6.
Points: Maurice Beatson (Dannevirke) 12 points, Simon Wilson (Waipukurau) 10, Tess Williams (Gisborne) 8.
Giltrap Audi young rider: Megan Lindermann Cohen (Clevedon) Lespos D'Quilly 1, Mathew Dickey (Taranaki) Kiwi Guard 2, Luke Dee (Gisborne) Ombudsman 3, Shaun Fannin (Hastings) Strathcarron Zurick 4, Alexa Randall (Auckland) Chairman 15 5, Jamie Thurlow (Feilding) Mister Pirate 6.
JLT Bloodstock pony grand prix: Rebekah Van Tiel (Pukekohe) Guthrie 1, Rebecca Porter (Hastings) Chobidong 2, Laura Lush (Auckland) Miss Munroe 3, Lily Tootill (Auckland) Millbrook 4, Morgan Percy (Palmerston North) Surprise Illusion 5, Lily Tootill (Auckland) Tallyho Bandit 6.
Cathay Pacific horse grand prix: Maurice Beatson (Dannevirke) Schimmel Warrior 1, Mathew Gilmour (Matangi) Belize Di Cantero 2, Julie Davey (Hastings) Air Hill Myka 3, Luke Dee (Gisborne) Ombudsman 4, Oliver Edgecombe (Waipukurau) Billistic 5, Lisa Coupe (Kumeu) Bates Amaretto MVNZ 6
. STH pro amateur rider: Zoe Shore (Ashburton) Olympia NZPH 1, Tim Finch (Waipukurau) Mr Munga 3 2, Caroline Tatere (Dannevirke) Grader 3, Geordie Bull (Taupo) Hunter Road 4, Chloe Akers (Palmerston North) Kiwi Motto 5, Chloe Akers (Palermston North) HR Kemosabi 6.
Iverquantel amateur rider: Dean Morgan (Cambridge) FIS Outrageous 1, Amy Playle (Gisborne) Oscar Star 2, Rosie Richards (Auckland) Firth View Dakota 3, Cindy Dames (Hastings) Chimney Creek 4, Jackie Jermyn (Cambridge) Landon Field 5, Olivia Gloyn (Palmerston North) Midway Ace 6.
KiwiSpan junior rider: Logan Massey (Dannevirke) Kiwi Ludo 1, Jamie Thurlow (Feilding) Clifton Ali 2, Lisa Hogg (Ohope) The Mighty Quinn 3, Tayla Mason (Wellington) Cufflink 4, Rebekah van Tiel (Pukekohe) Leeston Eagle 5, Nakeysha Lammers (Hikurangi) Cloud Nine 6.