The South Australian Derby is in trainer Danny O'Brien's plans for New Zealand-bred galloper Grinzinger Star, who has shown he is on target for a shot at the Group One race with a second-straight win at Caulfield.

Grinzinger Star chased down in-form Mr Quickie to win over 1600m at Caulfield two weeks ago and backed that up with a strong display to win Saturday's Bill Collins Handicap over 2000m against older horses.

With Damien Oliver aboard, Grinzinger Star ($3.70) settled midfield before chiming in strongly on the outside in the straight.

He defeated Divanation ($16), a daughter of three-time Melbourne Cup winner Makybe Diva, by one length with a short-head to Birth Of Venus ($11) third.

"He will run again in a fortnight at Flemington over 2000 metres and then he will potentially back up into the South Australian Derby a week later," O'Brien said.

"He needs another run at 2000 metres. He's a very robust horse and the seven-day back-up would be perfect going to a mile and a half after that.

"He was gelded at the end of the spring and that was his first racing preparation.

"He's definitely a more seasoned race horse now."

Grinzinger Star was unplaced when tried over 2500m in the Gr.1 Victoria Derby in his first racing preparation last spring.

While question marks remain whether he will be effective at that distance, O'Brien is looking to give the gelding his chance in the SA Derby on May 11 at Morphettville, with the right grounding under his belt this campaign.

Grinzinger Star was purchased for $90,000 out of The Oaks Stud’s 2017 New Zealand Bloodstock Premier Yearling draft.