Prepared by Stuart Webb, Crown Witness (image Darryl Sherer) had race fitness on her side having won her only two previous starts at Sandown and Flemington over the winter.
With a 2kg pull in the weights over the favourite Catchy, Ben Melham rode a forward race on the Crown Witness to sit outside the leader and she gave a good kick turning for home.
Catchy lost no admirers with her surging finish, but she came up short with Crown Witness holding a head advantage at the end of the 1100 metre sprint.
"To come out and beat a horse like Catchy… we're ecstatic!" said Stuart Webb.
Crown Witness was a $50,000 Inglis Premier purchase from the Golden Grove draft for Aquanita Racing and runs for Robert McLure and his family, who had so much success as part owners of the Stuart Webb trained multiple Group I winner Yosei.
"The McLure family have been big supporters of mine so it's a real thrill to see those colours win," said Webb, who is mindful of how much further Crown Witness can progress given she is still in her first preparation.
"We'll see how she comes out of this and how she is next week," Webb said.
"I think she could get to 1400 metres, but I'm not sure about the Thousand Guineas. We'd like to have a nice filly for the autumn."
Bred by Golden Grove, Crown Witness is the first winner for South African Group I winner Noble Heir (SAFr) and has won three from three earning $221,500 in prizemoney.
Golden Grove sold a Shamus Award filly from Noble Heir at Inglis Premier this year for $50,000 and she has another filly by the same sire to follow and was covered by him again last spring.
Crown Witness is the tenth stakes-winner for reigning Champion Australian Third Season sire Star Witness, who stands at Widden Stud at a fee of $33,000.