Just the Tip and Vincent Street pulled out ahead with a group of three, including Madonna Mia, while coming around the turn from the back stretch it was Thorn Prince beginning to make the move.
Yet under veteran jockey Darryl Bradley, Madonna Mia had her line and got the rail, fighting with Just The Tip as the field began to spread wide, and then with masterful timing they pulled away and just kept on going.
No one could answer as Tyne Cot left the run too late, and was eventually pipped right at the line for second by Grey Guru in a strong finish for Wanganui trainer Raymond Connors.
Finishing in 2m, 5.18s, the Cup victory made it three wins from three attempts for the Bradley and Madonna Mia combination, which included the Barber Groundspray Foxton Cup Open 2040m at Wanganui back in June.
While it was his first Wanganui Cup, Bradley wanted all due praise to go to Sharrock for setting the mare up perfectly for another crack at this racecourse and laying out the game-plan succinctly.
"Allan just has these horses spot on for these races," Bradley said.
"The blinkers were back on today.
"We had this race targeted a little way out.
"She was just travelling a treat, slide the turn and let the brakes go. She's flying."
The victory was also a delight for co-owner Paul Dombroski of Explosive Breeding Ltd, who had brought Madonna Mia, sired by stallion Red Clubs out of the dam Hill Of Hope, over to the Sharrock stables in 2013.
"It's a great thrill to win a race this old and prestigious," he said.
"She just kicked clear, we knew we were home and would be hard to run down.
"I can't give Allan enough credit for what he's done, and the staff at home of course.
"She's won two from two at Wanganui. It's just about my favourite course ... has to be my favourite course."
For Sharrock, even the change from an advantageous damp track to fairly dry conditions by race time was of no concern.
"She was probably as fit as I could have her.
"I was pretty confident, really.
"I set it for races, maybe I just get lucky. The harder you work, the luckier you get.
"To Darryl, I don't [usually] give 10 out of 10, but that was a ten."
Considering the future, Sharrock said the upcoming Manawatu and Marton cups were on the radar, but given this success it may be time to have a go for the big age fillies and mares races " the Black type events.
"I'll reassess and then let [her] screws go for a bit, then tighten them back up again."
The jockey club's Christmas event brought in $126,052 at the tote, which after the TAB-set budget is removed, was a profit level up $6000 more from last year.
Field said the walk-up crowd was good, as were the corporate sales, while a more beefed-up security team only had to deal with a couple of minor incidents, which was nothing like the few drunken scuffles seen in the public area at the end of the day in 2014.
"I'm very happy with that [tote] total. Everyone seemed to enjoy themselves.
"Excellent day, thank God the weather improved."