Smartest received a brilliant front running ride from Gary Carroll to break her duck in the six-furlong maiden at Dundalk.
The Michael Halford-trained filly had a healthy gap on the field from halfway and stuck on gamely in the closing stages as Cheveyo ran on to get within a head at the line.
"It was a great ride - brilliant. No doubt about that," said Halford. "From a bad draw he got across well. He sent her on and then got a breather.
"It was top class and he has made tremendous strides during the year. The 5lb probably made the difference in the end.
"She has run plenty of good races and deserved that. It is nice to get a winner for Mr (Michael) O'Leary who has given me a couple of nice yearlings again.
"I don't think we'll see her again now. There isn't much else for her and it's just nice to get a maiden with her."
