Ken Keys has come close to winning the South Australian Derby and the Cranbourne trainer returns on Saturday with a horse he rates his best chance yet.

Keys is chasing his first Group One win and Bring Something heads into the 2500-metre race at Morphettville as a winner of his past two starts including a two-length victory in the Listed Galilee Series Final (2400m) at Caulfield.

"I've never had a Group One winner," Keys said.

"I've run second in this Derby, I've run third in the Derby. I ran fifth last year in the Derby. I must be nearly due."

Keys finished second in the 2006 edition with Empire Gold - who later raced in Hong Kong under the name Plastic Polymer.

Four years earlier Lester Thunderwing was third in the Derby at Morphettville as a $101 chance while Like A Carousel was fifth last year.

Bring Something is on the second line of betting behind the Gai Waterhouse-trained Order Of The Sun who was a dominant last-start winner of the VRC St Leger at Flemington.

Bring Something has already had one shot at a blue-riband win, finishing seventh in the Victoria Derby (2500m) at Flemington last spring.

"He's the best chance I've taken to this race," Keys said.

"It doesn't mean it's going to happen. But you live in hope."

Bring Something, who will be ridden by Mark Zahra, will have to overcome an awkward barrier.