Saturday's 720m race was regarded as a three-way duel between Light Of Mine, Power Squeeze and Suribachi, but Derry, an $11 outsider in the five dog lineup, stormed home to win running away in 42.12.
Favourite Light Of Mine made the pace to the back straight but went amiss, allowing Suribachi to pounce on the lead.
Derry, who was third to the back straight and second for home, then finished too well for Power Squeeze, who had been last to leave the boxes.
After the Glenn Starr, trainer of Derry, said: "He is probably not good enough for group races but is a better dog than his WP record of just two wins from 14 starts suggests.
"Early in his career Derry took a tumble on the first corner at Wenty and ever since then he won't go hard around that bend, he gets very wide there.''
Fastest time of Saturday's meeting was posted by fifth grader Child's Play, who scored his first win in eight WP appearances, leading throughout in 29.65.
Child's Play, trained by Matthew Peisley, had been placed in four of seven previous WP appearances but until Saturday night's box six win had not won from further wide than box four.
Trainer Graeme Hughes said "I closed my eyes at the first turn" after his bitch Magnificent, the fastest qualifier, won Saturday night's Wagga to WP Final in the slow time of 30.70.
Magnificent, who had box five, led narrowly going into the bend but was badly checked by Cawbourne Cali, who pushed up along the fence to join the lead before running wide.
Magnificent's trainer Graeme Hughes said: "How my bitch stayed on her feet when she got that check I don't know, but I certainly closed my eyes when she and the dog in box one collided.''
Springview Sugar
Magnificent is a daughter of Feral Franky x Springview Sugar
Hughes bought Magnificent's dam Springview Sugar for $6000 after she had been with three different trainers, buying her as a potential brood bitch.
Goofy Ethics was having only her third start for trainer David Smith on Saturday when he scored an all-the-way win in a 520m fifth grade in 29.80, by far his personal best WP time.
At his first start for Smith's kennels Goofy Ethics finished second at Maitland before failing to beat one home at WP on February 28.
"Maitland is a good track for getting dogs fit, the long straights there seem to do their conditioning the world of good,'' Smith said on Saturday night.
"And when he finished last at Wenty at his previous start, Goofy Ethics was unlucky not to have finished close to the placegetters.
"He got tangled up early and his run was a lot better than it looked on paper.''
Jungle Johnny, who set a new Wentworth Park 520m record of 29sec on Thursday night, will be a shock withdrawal from the Wheeler Kennels Golden Easter Egg heats on March 21.
Jungle Johnny became a warm favourite for the series after shaving .04sec off the WP record held by Dalwhinnie and Cumbria Jack but the dog pulled up injured.
Owner John Maroun has confirmed the setback, saying: "Jungle Johnny sustained a stress fracture to his near-side hock and although he will be back eventually, we expect him to be out of action for two to three months.''
With Jungle Johnny no longer in contention, Cumbria Jack looms as the dog to beat in the $300,000 to the winner Easter Egg final on April 11, as there were no stunning performances at WP on Saturday night.
