Caught in a crossfire between ex-player Charlie Miller and former coach Frank Farina, Brisbane Roar mentor Ange Postecoglou came out with guns blazing on Friday ahead of a season-defining week.He dismissed Miller's criticism of his coaching approach as "absolute garbage" before delivering a backhander to Farina, saying he wanted to build a successful Roar club."That's something that hasn't happened before," said Postecoglou, who took over the reins from a sacked Farina.But Postecoglou was clearly most unimpressed with Miller who signed with rivals Gold Coast United on Friday after sensationally walking out on Brisbane when his future could not be assured.Miller didn't waste time firing barbs, claiming the Roar mentor "wanted to move the older players out of the team ... because they like to have a bit of fun and enjoy their lives".Postecoglou initially wished Miller "all the best" after the Scottish playmaker signed on as a short-term injury replacement for United, ensuring he will feature in this weekend's trip to Newcastle.Then he let rip."If I was coach for my son's under 10 side I could understand (Miller's comment) but the rest of it is just garbage," he said."I assume sportspeople get their enjoyment out of being successful and improving, and trying to win things."You talk about fun. I don't know how much fun it has been for our supporters watching us this year."I don't know how much fun it has been for the owners who have put in good money to watch us play this year."That's not what elite sport is about, and everyone knows that."So some of that is absolute garbage."Postecoglou also responded to Farina's News Limited column on Friday which claimed letting go of Miller was "inexcusable"."Frank writes an opinion piece so it would be pretty boring if he didn't have an opinion - but that doesn't mean we have to agree with it," he said."It hasn't been a real discussion point around the club."The only disappointing thing about what Frank said was that he had a shot at the people running the club."I can assure everyone that Charlie's decision was my decision, it was a football decision - I will be judged on that."It's about what I think is best for our footballing future."I will continue to make decisions that I believe will take us in a new direction that I hope will create a successful Roar - that's something that hasn't happened before."It is hardly what Postecoglou needs ahead of three crucial games in a week starting with Saturday night's clash with Adelaide United at Suncorp Stadium."We can really turn our season around with these three games," Postecoglou said.They play another home match against North Queensland Fury on Wednesday before a trip to the Central Coast next Saturday.