"Today was the day," he told a capacity crowd at the Hawke's Bay Showgrounds.
A 1988 Olympian, Beatson said his prizemoney will come in handy for his show-related bills.
"I brought seven horses here and it was a quiet show until today," he explained.
One of 28 starters in the class, Beatson was full of praise for the six Aussie riders who helped "make it a quality event" and the work done by HOY director Kevin Hansen.
"The work Kevin did in helping to organise the Long White Cloud Series which began in Dunedin last month can't be forgotten either," Beatson said.
"When Kevin gets a vision he goes with it. We can't ask for any more prizemoney in this economic climate ... this is magic."
Kermond praised the work the ground staff did in the drought-like conditions to produce quality surfaces all week. While steady rain for most of the Olympic Cup made conditions difficult, Kermond said competitors just had to adapt and it added to the challenge.
Another Aussie visitor Alison Rowland, riding Bickley Brook Bella, was third with a total of five faults. Had she produced a clear round in her second tilt she would have won but she collected four faults and slipped to third.
Nineteen-year-old Hawke's Bay hope Luke Dee and Ombudman had 12 faults in his first round and 17 in his second. The Taupo-based Hawke's Bay-raised Daniel Meech had 13 faults in his first round and didn't qualify for the second.
However their day will come. Yesterday it was Beatson's again and it was appropriate the majority of the crowd remained for the prizegiving to salute the king of the Hawke's Bay equestrian scene.
Thirteen combinations - those with 12 faults and less - progressed to the second round.
Missing from the line-up was four-time Olympic Cup winner Katie McVean, who was without her star Dunstan Daffodil and started two youngsters in the class.
Taranaki's Vanessa Way again won the Dressage Horse of the Year with NRM KH Arvan, which she took to the UK last year in an effort to make the London Olympics. It is their second top title at HOY.
Way showed the benefit of her months of training with world-class dressage rider Carl Hester. She also won the level five title with NRM KH Allandro and was reserve in level six with NRM Arawn.
Earlier in the show Mystery Creek's McVean won the BetaVet NZ Speed Championship on Dunstan Zasjany D.