Flemington trainer Brian Mayfield-Smith says the decision to geld Gran Sasso at the end of last year has been the key to his significant improvement this campaign.Gran Sasso has always been a consistent sprinter with six wins and 12 placings from 23 starts but has taken his career to a new level through a focus on straight racing at Flemington.A dual All Victorian Sprint Series heat winner up the straight at his last two starts, the four-year-old has taken his rating from 89 to 101 this campaign

Flemington trainer Brian Mayfield-Smith says the decision to geld Gran Sasso at the end of last year has been the key to his significant improvement this campaign.

Gran Sasso has always been a consistent sprinter with six wins and 12 placings from 23 starts but has taken his career to a new level through a focus on straight racing at Flemington.

A dual All Victorian Sprint Series heat winner up the straight at his last two starts, the four-year-old has taken his rating from 89 to 101 this campaign.

He faces his biggest challenge with 58kg in Saturday's $150,000 final (1200m) at Flemington but is expected to handle the extra load with TAB Sportsbet installing him at the top of betting at $3 ahead of Midnight Mustang at $4.40.

Mayfield-Smith is hopeful this campaign will form a platform for better races in the spring now that Gran Sasso has hit such a purple patch of form.

"Really, the key was getting him gelded at the end of his last preparation," Mayfield-Smith said.

"He has come back pretty good and he does like the straight."

Gran Sasso hasn't finished further back than fourth in five runs up straight and three starts ago just missed out on winning his first stakes race in The Straight Six when Midnight Mustang grabbed him on the line to win in a photo-finish.

"He was unlucky that day," Mayfield-Smith said.

"He races best when he is held up but he lobbed on the pace and was left too exposed."

Next start Gran Sasso was explosive as he burst to a 3-3/4 length win over Time Matters and Midnight Mustang in the third heat of the sprint series over 1200m.

The winning margin was not as empathic last week but nonetheless he was impressive as he came back in distance to 1000 metres and beat Allied Force and Group One placegetter and straight specialist Grand Duels.

Mayfield-Smith said Gran Sasso had a strong constitution and was ready to back up this week.

"It was always the plan to back up into the final and his run last Saturday didn't strain him at all," he said.

"He has done very well this week and everything looks spot-on with him.

"We will run him in the final and then freshen him and try and win something decent in the spring."