South Australian Derby contender Detonator Jack will attempt to win the race at his fourth race start.

Highly fancied South Australian Derby contender Detonator Jack will need to break new ground if he is to win the Group 1 race at Morphettville. 

Detonator Jack will be lining up for his fourth start in the 2500m Classic on Saturday and the only one to come close was Irish-bred Russian Camelot who won the Derby two years ago at start number five. 

Over the last 10 years, the average numbers of starts of Derby winners is 10.6, while Qafila won the race for Lindsay Park at start number 17. 

Detonator Jack is aiming to give Ciaron Maher and David Eustace back-to-back victories having scored last year with Explosive Jack. 

The only thing both horses have in common, according to Eustace, is they are by Jakkelberry.

Detonator Jack scored at Bendigo on debut, progressing to Sandown to win over 1600m and then again at Sandown over 2100m in his three career starts to date. 

Explosive Jack was having his eighth start when he won at Morphettillve after previous Derby wins in Tasmania and Sydney. 

"They both took a while for the penny to drop but Detonator Jack would probably have a bit more toe than Explosive Jack," Eustace said. 

"He's versatile that way but Explosive Jack is probably a bit tougher and got to the mark a bit quicker, but to me it's his race to lose and he seems in really good nick." 

Tuesday's barrier draw was not kind to Detonator Jack, barrier 15, although he will come in four spots if the four emergencies do not gain a start. 

Detonator Jack sits on the second line of betting at $3.80 behind Godolphin galloper Alegron ($2.80). 

Maher and Eustace also have Texas Tea in Saturday's race, currently the first emergency. 

Texas Tea had its first start for the new stable, finishing third at Mornington on April 28. 

"He's quite a nice horse. I quite like him. He's going to be $26, but he could run a race," Eustace said.