The former Olympian and world cup finalist headed off 13 other combinations at the Central and Southern Hawke's Bay Show in Dannevirke in the fifth round of the New Zealand series on his partner Sally Clark's grey Zibbibo.
Beatson also placed third on My Gollywog. He bred both horses at their Dannevirke base.
Beatson and Zibbibo, who is by Wishing Well, were the only combination to go clear in the first round of the Kevin Hansen designed course, but picked up a time fault for their caution.
Ten combinations went through to the second round, where Beatson and Zibbibo dropped a rail but still held their lead.
As Zibbibo was not Beatson's nominated horse, the second placed Anna Trent (Hawke's Bay) and Cortaflex Muskateer NZPH took top points.
With just two rounds left, and only the top four rounds counting for the series, Beatson, who took over the ride on Zibbibo only this season, has a slim three-oint buffer over Trent.
He was chuffed with the efforts but low-key about his results. "A lot of hard work goes into these horses, so it is nice to get something back," he said.
Beatson has before represented New Zealand at a world cup final - this year's one is in April in Las Vegas.
"It will all come down to that last round," says Beatson.
The final is being held in Gisborne from January 23-25.
Katie McVean (Mystery Creek) and Dunstan Forest II won the one star horse grand prix, with Jake Lambert (Matamata) on Co Calico taking the pony grand prix.
Points after five rounds (best four to count): Maurice Beatson (Dannevirke) 52 points, Anna Trent (Hawke's Bay) 49, Simon Wilson (Waipukurau) 43, Ike Unworthy (Tauranga) 32, Robert Steel (Hawera) 31.
Six year old: Maurice Beatson (Dannevirke) Winter Warrior, Kim Best (Otane) Photogenic NZPH, Robert Steele (Hawera) Up To Date, Daniel Webb (Hunterville) Abernaki Chief, Anna Trent (Hawke's Bay) Cortalfex Party Girl NZPH =1.
Five year old: Kim Best (Otane) IQ, Melissa McBreen (Gisborne) Cavaletto, Sally Clarke (Dannevirke) Omicron =1.
One star horse grand prix: Katie McVean (Mystery Creek) Forrest II 1, Oliver Edgecombe (Waipukurau) JJ Freelance 2, Maurice Beatson (Dannevirke) Jedi Warrior 3, Bernard Denton (Gisborne) Suzuki 4, Katie McVean (Mystery Creek) Dunstan Delphi 5.
Pony grand prix: Jake Lambert (Matamata) Co Calico 1, Jackie Gowler (Feilding) Peanut Hine 2, Hannah Burnett-Grant (Taupo) Mighty Maximus 3, Greta Porter (Hastings) Chobidong, Gemma Booth (Wanganui) Miss Munroe, Courtney Myers (Hawera) My Dreamworks and Elliott Muller (Hawera) Our Donovan =4.