After the Roar's 12th-placed finish last season, Valkanis said that he wanted to put "the roar back in Brisbane" and this was a promising start in front of 6218 fans at Suncorp Stadium even amid his own family drama with his son.
The 19-year-old Roar defender was dismissed in the 58th minute after acquiring his second yellow card for a late challenge on Harry Sawyer.
Still, it couldn't stop the Roar winning their season-opening match for the first time in six years. Last season, it had taken Brisbane 13 matches to notch a win.
The coach said his son was "apologising for leaving the team with 10 men".
"Sometimes things happen for a reason," Valkanis said.
"It's gone in a good way in terms that we had to roll up the sleeves and really work hard and prove the togetherness we have been building
"We've been saying ... anyone, anywhere, anytime you fight to win and find a way to win."
Bulls coach Mile Sterjovski said the style of football played by the Roar under Valkanis "surprised" him.
He said there was "a lot of time-wasting" and he thought the Roar's football would be "a lot more positive".
Valkanis hit back.
"I don't know what they expect, whether they expect us to lie down and let them beat us," he said.
"Maybe they found a Roar that is putting the roar back into Brisbane and want to fight until the very end. That's what we showed."
The hosts had been totally committed and played with more physicality than the Bulls in what was a brutal 100-minute clash marred by multiple fouls..
The Bulls were unable to break down the defiant Roar who showed commendable resilience.
Earlier, Roar skipper Jay O'Shea, the club's best player for multiple years and man of the match, nailed a 38th minute penalty to send supporters group 'The Den' into raptures.
The 37-year-old Irishman had already been a shining light in midfield with his cunning crosses and free kicks.
It was a sneaky short free kick to forward Georgios Vrakas that set the goal-scoring opportunity in motion.
Vrakas drilled a cross and all veteran Bulls skipper Luke Brattan could do was get his hands in the way inside the box, giving O'Shea the penalty chance which he drilled into the top right corner of the net to give goalkeeper Filip Kurto no chance.
Impressive 21-year-old Roar midfielder Samuel Klein was heavily involved early and went close to getting hold of a pinpoint cross by O'Shea at the far post.
It was the visitors who had the best scoring opportunity when a raking run by forward Chris Ikonomidis and a slick cross was headed wide by Dean Bosnjak.
The Bulls looked most dangerous when Socceroos midfielder Anthony Caceras roamed forward to his left and right but it happened far too infrequently in the opening half.
Caceras sent a perfect long ball onto the head of Bosnjak straight after the break but once again the chance was spurned.
After Valkanis was marched, the hosts hung tough in a gruelling encounter that went to the 100th minute.
