"I am really frustrated that I was sent off after the game for no reason, for no reason whatsoever," Valkanis fumed post-game in Redcliffe.
Valkanis got a yellow card in stoppage time. He said he then asked a question to referee Lachlan Keevers post-match, who produced a red.
"I asked a question, why I got the yellow card. And he said to me, 'move away'," Valkanis said.
"We are on the sideline. We ask questions. We don't get answers. It is like we are playing against everyone every single time."
Valkanis said it was "only fair" that he should be able to ask a question and be treated with respect with an answer.
"I came back here to Australia for my kids to have a really good life and I am thinking what has happened in this country when we cannot ask a question," he said.
"It is not right that anyone like that is arrogant and does not answer."
Valkanis said he felt the Roar had been pre-judged and attacked from the pre-season.
Central Coast veteran Storm Roux was the unlikely goal-scoring hero on Saturday.
The 79th-minute winner was just Roux's ninth goal in 285 A-League matches but a vital one at Redcliffe in the context of his side's season.
The Roar's miserable January, when they lost five of six games, continued into February.
The Mariners, celebrating consecutive wins for the first time this season, were last under coach Warren Moon before Christmas, but are now just four points outside the top four.
The previous match between the sides on December 31 was explosive, won 2-1 by Brisbane away. Valkanis was red-carded and got a week's suspension.
Former Roar mentor Moon blew up after that match, calling what transpired "a disgrace". The Roar fired off a legal letter after his comments.
There was an element of tension that bubbled to the surface at various stages of Saturday's match, with Roar football director Shane Stefanutto getting a yellow card on the bench early in the second half.
The tension escalated at the death and after the whistle.
Socceroos striker Nick D'Agostino slammed home his first goal for Brisbane since his last starting appearance for the club in 2019.
D'Agostino had come off the bench in his previous two matches of this campaign. His last starting jersey for Brisbane was back in April of 2019, when he scored in a win over Adelaide.
He was a target for Roar crosses on Saturday, but Mariners defender James Donachie enjoyed the marking challenge and prevented any damage until the 44th minute.
Nice work in midfield by Sam Klein and a cross into the box was swooped on by D'Agostino, who finished with panache.
The Mariners hit straight back in stoppage time when Miguel Di Pizio got on the end of a Lucas Mauragis cross to complete a frenetic finish to the half.
D'Agostino, who had come off the bench in the previous two games after signing in the January transfer window from Viking FK, was replaced in the 69th minute after his longest stint so far for the Roar.
Japanese import Kaito Taniguchi had a shot when he came off the bench in the second half on his ALM debut. Roux composed himself and slammed home with his left foot.
Roar midfielder Noah Maieroni will miss the next match after his fifth yellow card of the season.
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