Hastings-trained San Pedro began well to lead as the field swept past the grandstand for the first time, before Ascolini took off to set a hectic tempo.
The field spreading around the back of the course actually did Cassini a favour, freeing up space for the defending champion to do her thing.
Her Awapuni trainer Mark Oulaghan felt the firm ground was going to suit his champion and there was little concern as Ascolini set a challenging lead.
"Things can change, these lightweights can be a danger when they put the break on.
"She got home pretty well."
He could not fault the temperament of Wanganui jockey Johnathon Parkes, who had stepped in to take the reins.
"He rode it perfect at his first ride on the horse."
Parkes was delighted to have met the pressure of riding a favourite and the defending champion to another success.
"The horse looked in very good order," he told the crowd.
"It's good to win the Wanganui Cup, I'm a local boy so it's a big thrill."
Later, Parkes said the spreading field "plucked" Cassini off the fence and a little daylight was all they needed.
"I got a nice trip, I just wanted to get off the fence on the straight."
Last year Wanganui's Lisa Allpress took Cassini to the post, but with Saturday being the start of a six-day suspension her participation at the course was limited to spectator and tipster.
Parkes has a busy upcoming Christmas racing schedule which will see him ride in New Plymouth on Thursday and Wellington on Saturday.
For Cassini, who is in foal, Oulaghan is eyeing another 2011 repeat at the upcoming Manawatu Cup, then possibly the Triple Stakes in January.
At 7 years old, that will probably be the end to her track career, he said.
Also smiling at the finish was Wanganui Jockey Club operations manager Bret Field after another successful Christmas event.
The club had sold 750 packages, "that was better than expected" and had all been snapped up two months in advance.
On-course turnover was $148,000 it had been $150,000 in 2011 with an 11-race programme.
