"In 35 years I have never had a horse work so well," he told the Herald.
"I gave her five days off after the Spring Classic but if anything that has brought her on.
"She is spot on for this and anything but a win would be a huge disappointment."
Sharrock says he pays jockey Opie Bosson to worry about getting Shez Sinsational off the rails from barrier one, where her rivals would love to trap her given the chance.
"He has 2000m to get her off and he knows what he is doing.
"But it might actually give us a chance to try something different with her and ride her handier.
"She settled in the first four when she won the Darci Brahma last season so don't be surprised to see that again."
Bosson is reunited with Hidden Asset, who he has ridden just once, for a win at Hastings two starts ago, in the last race on today's drawn-out programme.
Hidden Asset was left flat-footed in a muddling 2400m event last start and would appreciate a stronger pace today as he heads towards the Waikato Cup.
It could prove a profitable day for Bosson as he is also aboard the highly rated Wisecrack, who will appreciate the 2200m of the opening race.
Like Hidden Asset, whom he raced in the 2011 NZ Derby at Ellerslie, Wisecrack is being set for the late spring and early summer cups.
Distance racing should be his forte, being by High Chaparral from the classy Grosvenor mare Limerick.