The 26.9-kilogram pocket rocket was slowly away from box one and bumped with Pyro Bob (box two) in the early stages.
Despite finding trouble, the black bitch was able to push up along the fence, taking the lead in the run to the line on the first occasion.
Setting up a big break down the back, Lantana Lass strode to the line to score by two-and-a-half lengths over a fast-finishing Pyro Bob in 30.61.
A daughter of Fabregas and Graduation Girl, Lantana Lass has now won five of her six starts for Brett and owner Lenny Antonio.
The second semi-final on Saturday night was won by Wivenhoe Pocket trainer John Mccarthy who put the polish on Rather Dapper.
A finalist in this year’s Group 2 Vince Curry Maiden, Rather Dapper was fairly away from box seven, but got room to move and was able to slip into second spot behind Maurice Minor (box six) around the first turn.
Down the back Rather Dapper took control of the race and never looked in danger from that point onwards, sprinting to the line to score by two-and-three-quarter lengths in a fast 30.49.
Maurice Minor held on to run second and will also qualify for next week’s final.
Mccarthy qualified two for the final, with Rather Dapper’s litter brother Slick (box six) running second in the third semi-final.
The son of Dyna Lachlan and Pearl Za Zinger was midfield at box rise and quickly mustered enough pace to find himself in third position early.
However, by that time, Tony Apap’s Enjoy The Show (box three) was already off and gone after a brilliant beginning and proved too nippy in the run to the line.
At the finish the son of Shakey Jakey and Tina’s Show, a half brother to top Queenslander Outside Pass, scored by one-and-a-half lengths, with the time recorded being a fast 30.44.
Tom Tzouvelis, who already qualified Maurice Minor through to the decider, also took out the final semi-final with his consistent chaser Must Be Max.
The brindle dog showed enough speed to lead from box five, but was trapped wide through the first turn and stayed off the track down the back.
Cutting down to the rails off the back straight, the son of Glen Gallon and Mini Pod went wide once again in the home straight, but was able to do enough to hold off a late challenge from Invergarry Lady (box four) in 30.69.
Having started his career in Darwin, Must Be Max is now a winner of 11 of his 19 starts with an additional five minor placings.
The final of the Group 2 Ipswich Auction Series will be held next Saturday night and is worth a hefty $70,000-to-the-winner.