Miss Key added to her love affair with Wagga with another impressive win.
She made it three wins from four attempts on the track for Collector couple Kim and Andrew Mulrine.
Andrew Mulrine is hoping she can repeat the dose in next week's final after taking out the third heat of the GRNSW 5th Grade Series (320m).
Coming off a placing at Dapto two starts ago, Mulrine was pleased with her efforts.
"They usually don't need too many looks here but she's gone well after trialling well at Dapto last Friday," Mulrine said.
"She seems to love the place."
Miss Key was the slowest of the three heat winners.
However she was by far the most comfortable winner.
She swooped on Corrupted to win by 5.5 lengths in 30.76 seconds.
In comparison Milly's Last won in 30.61 seconds for Peter Sims to be the fastest qualifier.
Causing an upset, the $11 chance finished 1.5 lengths clear in the opening heat while Soul Searcher edged out Ralph to win the second heat in 30.68 seconds.
Mulrine is looking to draw another inside alley in the final.
He believes it is where Miss Key does her best work.
"Inside boxes suit her better than the outside boxes as she's had two ones and a two now (at Wagga) and has won the three of them from inside boxes," Mulrine said.
"She does like the inside boxes better than the outside so hopefully next week she can get an inside box.'
"Boxes do win races."
The win sees Miss Key bring her record to five wins and two placings from 13 starts.
She has raced over the 600 metres at Dapto before the series and Mulrine is happy with how she is progressing.
"I'm pretty pleased with her at this stage of her career," he said.
"She is bound for better things.
"She can actually get further and we did put her over the 600 at Dapto in her last couple of goes, and she was a bit unlucky in her first start, but she can get more ground."
The race has been on the agenda for the Collector couple for a while.
They were hoping to have littermate Fox Key also compete before injuring himself in a trial.