Trainer Danny O'Brien will chase valuable black type with improving filly Indulge after her win at Sandown on Wednesday.

O'Brien trained Indulge's dam Splashing Out and the filly's sister Shopaholic to win at Group level and is hopeful Indulge can join that list.

The filly took her first step on that road with a breakthrough city win at Sandown.

Ridden by Damien Oliver, Indulge rode the pace throughout before holding off a late challenge from So You Drink to take out the Cable Beach Club Resort & Spa Handicap by a half-head.

O'Brien has had a long and successful association with the filly's owner Garry Chittick and Waikato Stud which bred Indulge.

"We trained the mother Splashing Out, who ran second in a Coolmore (Stud Stakes) and was a Group Three winner, and the full sister Shopaholic who was also a multiple Group winner for the stable," O'Brien said.

"She's certainly got some big shoes to fill and has always shown more ability than what she's shown on the day at the races.

"She's put two together now and hopefully she's getting the hang of it now."

Indulge was successful in maiden grade at Geelong before making the progression to city company on Wednesday.

O'Brien said he would look at stepping her up to better class three-year-old fillies races during the autumn in the hope of gaining black type to increase her broodmare value.

"That's why they come over here from New Zealand, to get some good Australian black type and then go back home to Waikato and do their job," he said.

O'Brien said he left the riding tactics up to Oliver after Irish apprentice Kieran Shoemark led on Indulge when she "fell in" at Geelong.

"I just left it up to Damien today," O'Brien said.

"He's the guy to do that job."