There are some "sleepless nights" ahead for New South Wales coach Brad Fittler after Queensland provided a wake-up call in their 18-14 State of Origin series-opening win.

Key points: NSW coach Brad Fittler has some selection headaches after his team went down 18-14 to Queensland at Lang Park in Origin I

NSW coach Brad Fittler has some selection headaches after his team went down 18-14 to Queensland at Lang Park in Origin I Sin-binned centre Latrell Mitchell is under pressure, while Fittler's under-use of five-eighth Cody Walker has been questioned

Sin-binned centre Latrell Mitchell is under pressure, while Fittler's under-use of five-eighth Cody Walker has been questioned The second State of Origin game will be held in Perth on June 23, with game three in Sydney on July 10

But Fittler hinted that his defeated Blues could rest easy about team changes for this month's Origin II if they back up for their NRL teams.

Fittler's worst nightmare was realised when Maroons playmakers Cameron Munster and Daly Cherry-Evans, plus livewire full-back Kalyn Ponga, cut loose in the second half to help inspire a comeback victory.

The trio helped unleash man of the match Dane Gagai, who scored two second-half tries in four minutes to snatch victory away from NSW.

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"Munster, Ponga and Cherry-Evans started skipping across the park and got everyone nervous (in the second half)," Fittler said.

When reminded that the trio had been his worst fear ahead of Origin I, Fittler said: "It means more sleepless nights."

To make matters worse, NSW's 2018 standout — centre Latrell Mitchell — hardly fired a shot after being smothered by Queensland's defence.

His frustrating match was marred by a 58th-minute sinbinning for a professional foul that turned the match on its head, helping Queensland break an 8-8 deadlock.

"I felt at times they looked like they isolated him. They put a lot of pressure on that side," Fittler said of Mitchell.

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"They did a pretty good job in defending that side."

Half-back Nathan Cleary and debutant pivot Cody Walker appeared most under pressure ahead of June 23's Origin II in Perth.

Cleary failed to ditch his hot and cold form at NRL battlers Penrith, while South Sydney's form playmaker Walker was surprisingly subbed in the 57th minute with the game on the line, replaced by Jack Wighton.

Fittler baulked at making team changes but made it clear his incumbents had to go back to the NRL and prove their worth before he named his Origin II side.

"They have to go back and play for their club. Our theory has always been blokes who play well for their club (get picked)," he said.

"I really expect them to go back and play well for their club."

Dane Gagai scored two vital tries for the Maroons in Queensland's Origin opener win over NSW. ( AAP: Glenn Hunt )

Still, Fittler admitted they had some work to do to wrestle back momentum after Queensland reeled in an 8-0 half-time deficit.

"They missed the occasion. There was a lack of communication, a bit of panic that I didn't see much of last year," Fittler said.

"You get to games and feel like you are part of a wall and there are times you get to games and think you are on your own — it just felt at stages they felt like they were on their own."

AAP