The Queensland Derby is back in the sights of Nobu who has shown he has his campaign on track with a dominant victory over 1800 metres at Randwick.

Trainer Chris Waller sent Nobu across the Tasman for the New Zealand Derby in early March but the gelding was disappointing, beating just one runner home.

He returned to Sydney and ran second in a benchmark race over 1550m at Randwick last Monday week before stepping up in distance on Saturday to beat stablemate Duchess Of Lennox by 4-1/4 lengths with another stablemate Ombudsman a close third.

Punters took note of his previous start and sent Nobu out the $4.20 favourite and he raced accordingly, launching his bid at the top of the straight.

He quickly reeled in the leaders before spearing away with Tommy Berry having time to take a couple of looks at the infield screen to see how far in front they were.

"He has come on in leaps and bounds since arriving back from what was a bit of a disappointing trip to New Zealand for the Derby over there," Waller's racing manager Charlie Duckworth said.

"Obviously he is right back on track now with the writing on the wall from his last start around this track.

"He will go onwards and upwards from here and hopefully he can link up with the rest of the potential Derby runners.

"A trip away for a young horse can do wonders for them and since he has come back he has really switched on."

Berry said Nobu had improved since he last rode him, crediting the trip away.

"I had a bit to do with him in his last preparation and he was a little bit physically weak last prep," he said.

"Chris taking him to New Zealand even though it did not work out for him he has come back a lot tougher and a lot stronger and you saw that today.

"He is a completely different horse to what I was riding last preparation."

The Group One Queensland Derby (2400m) is at Eagle Farm on June 8.

Duchess Of Lennox is also in the mix for a trip to Queensland for the Oaks (2400m) a week before the Derby.

"She's a lovely filly. She's very raw but will take a lot of learning from that," he jockey Kathy O'Hara said.

"She can take the steps she'll need to to make it to a race like the Oaks in Queensland."

All three placegetters are by French Derby winner Reliable Man who Waller trained to win the 2013 Queen Elizabeth Stakes.