Until her last start in the Teeny Teeny Stakes harness racing trainer Anthony Bucca was unsure whether his four year old Rainbow Dasher was going to be competitive against the state's best mares.

However a second placing in the $40,000 feature was enough for Bucca to believe his mare can beat the best and win this Saturday night's Ranji Bill Stakes at Tabcorp Park Menangle ensuring her a start in next month's Ladyship Mile.

"It is always hard for the four year olds to graduate to racing against the open aged mares and I was still unsure whether Rainbow Dasher was ready to go up against the best this season," Bucca said.

"She was a very good two and three year old but it is a different class altogether when you hit the open ranks but her second placing behind Our Torias Secret was enough proof for me that she can handle this class of racing."

Rainbow Dasher won a race at Menangle as a three year old in 1:53.0 but is still yet to win since turning four.

"I think a lot more four year old only racing should be conducted because the above average two and three year olds come back as four year olds on hard marks and it makes it very tough for them to be competitive but my mare has been placed four from five this season so it is only a matter of time before she wins."

Bucca is confident Rainbow Dasher could lead on Saturday night but he is unsure if he wants to attempt an all the way win after drawing barrier one.

"I think I can lead but she is very versatile so really I can do what I like, they ran a 1:54.0 mile in the Teeny Teeny Stakes after running a slow second quarter, I can't wait to get into a race where the speed is on from start to finish because that's when I think you will see the best of her."

"Luke McCarthy holds the key to the race with four runners engaged and I think his mare Our Sixpence is the one to beat."

Courtesy of Dale Walker (HRNSW)