Williamson scored her first quinella as a trainer when Majicion ran into second placing behind Muscle Pat in race 1.
Muscle Pat had not been sighted at the races, or on a trial or workout track, since his last start on the West Coast in March.
Since then, the horse had moved in to semi-retirement and was relegated from racehorse to training pacemaker at Williamson's stable.
Ironically, that move has helped revitalise his career.
"I have been using him as a pacemaker for a couple of 2yr-olds we gave a couple of trials," Williamson said.
"That kept him reasonably fit, and then I needed something to work The Dominator with down at the Phar Lap [Raceway].
"Poor old Muscle Pat gets annihilated by him when we turn in to the straight."
Consistently being beaten in his training runs would be enough to put most lower-grade trotters off their game, but it looked to have the opposite effect on Muscle Pat last night.
He did to his opposition what The Dominator does to him in training each week.
It was slightly fortunate that Muscle Pat got the opportunity to emphatically demonstrate his renewed vigour for racing.
Williamson admitted she had no intention of racing the horse after he had shown his worth as a pacemaker in trackwork.
"That is why he hasn't been to the trials or anything, because I didn't have any intention of sending him anywhere [to race], to be honest," she said.
"When I had the opportunity to put him off 30m at Forbury I thought `the float is going anyway, so he may as well go with Majicion."'
Williamson took bragging rights over her partner, Steven Bell, with her quinella result.
Williamson races Muscle Pat, while Bell races Majicion with another Levels trainer in Murray Tapper.
Tapper's night got even better when he produced Superstar Legend to win race 2.
West Melton's Michael House produced the kind of brilliant form his stable has been known for in the Central Districts this season with four wins.
House produced Little Rain to win race 6, Honour The Bet to win race 4 and Kruizr to win race 9. The trainer then capped his big night out by winning the Forbury Park Claimers Series with Anna Barclay.
His quadruple took House to 85 wins this season, easily his best term in 31 years as a trainer.
Little Rain, Honour The Bet and Anna Barclay helped driver Blair Orange notch a winning treble in the sulky.
Those results took saw Orange hit 1800 career victories as a reinsman in New Zealand.
Orange has 193 wins this season, meaning he is set to win 200 races for a second consecutive term.
