Thijssen unsure on Henrique injury
The visitors stunned the Reds in the 18th minute when Henrique cracked a beauty from 25 yards and almost doubled the buffer moments later when midfielder Dimiri Petratos had two bites at the cherry.
Henrique's goal proved enough despite Adelaide completely dictating the entire second half and peppering their goal, albeit unsuccessfully, against the error-prone Roar.
For Thijssen, the good fortune was well deserved after he was left miffed at losing last week to Melbourne City at AAMI Park courtesy of a contentious penalty decision.
"Last week (against City) maybe we played a little better and we were unlucky to lose," Thijssen said.
"Today we were a bit lucky to win. The first half we were on top ... if you look at the chances we could have been 3-0 up.
"In the second half we lost the ball so quick that we came under pressure.
"If you don't keep the ball you get these sort of games where you have to battle for three points. We were a little bit lucky to win."
"We lost last week because of that referee decision. We got one back today a little bit."
Henrique is one shy of Wellington Phoenix spearhead Nathan Burns on the goal-scoring leaderboard and has almost two-thirds of Roar's total goals this season.
But a scare infiltrated the Brisbane camp when he sustained a right knee injury after a Dylan McGowan tackle from behind, causing the diminutive Brazilian to substitute out ofthe contest before half-time.
Thijssen is unsure of the seriousness of Henrique's injury but is buoyed by the fact the Roar does not play again until after Christmas.
"Henrique had the knee injury and he's very important for us, especially on the break - he's young and scores the goals," Thijssen said.
"We missed him a lot (in the second half). Hopefully he's back soon.
“We have a little break now that helps. It's nice having a break and with the three points - it gives a good feeling."
The stirring win provided a bright farewell for departing captain Matt Smith after a turbulent few days.
Earlier this week, Smith announced he would be leaving Brisbane to join Thai club Bangkok Glass.
Thijssen left Smith chained to the bench until the 90th minute and admitted the captain's mid-week decision caused a distraction.
'Yes, of course," Thijssen said. "He made the decision and he's thinking about his future - and I have to think the same.
"I explained to him that I cannot let him play and keep somebody on the bench who I have to use next week.
"I know he's leaving and as coach you have to make a decision. It was not difficult.
"In the end we tried to keep the 1-0 and you bring a change because you want to give him the last minutes to play for Roar."