Ger Lyons added the opener at Dundalk to his first race success at Cork when Muckle Bahoochie ran out a convincing winner of the two-year-old maiden on the all-weather.
It was a welcome winner for Keagan Latham as it was the South African's first success of the season.
He gave the Moss Vale filly a positive ride, soon getting to the front, and keeping on gamely from over a furlong out to record a length success.
8/13 favourite Danziger had looked a big threat early in the straight but faded inside the final furlong and Rockview Diamond eventually came through to take the runner-up spot.
The winner had finished mid-divison on her debut at Navan. She attracted support this morning from 12/1 into 11/2 and was eventually sent off 7/1 on course.
"She came out the Navan race with very sore shins and I was gutted with how she ran. I think she's a Listed filly," said Lyons.
"I told the owner I would be gutted if she didn't win tonight. She'll get an entry for the (Listed) Marble Hill Stakes (Curragh 21st May).
"I have a nice bunch of fillies but they haven't been running as expected. My two-year-olds seem to be taking a bit of time to come to hand.
"I'm really aiming everything towards Royal Ascot as that the type of two-year-old races I want to be winning."
Lyons had also struck in the opening two-year-old maiden at Cork with Greek Canyon also by Moss Vale. Both winners picked up a €10,000 bonus thanks to the Racing Post Yearling Bonus scheme.