Johnathan Thurston ready to attack in State of Origin decider at Suncorp Stadium.

JOHNATHAN Thurston will go into the Origin decider armed with a new attacking approach, revealing his personal struggle to replace Darren Lockyer.

JOHNATHAN Thurston says he will go into the Origin decider armed with a new attacking approach as the Maroons maestro revealed his personal struggle to replace champion pivot Darren Lockyer in the No.6 jumper.

Thurston produced his best performance of the year in the Cowboys' 12-0 defeat of the Broncos on Friday night and admitted he was a man on a mission after being nullified by the Blues in Queensland's 16-12 loss in Origin II two days earlier.

In a scathing assessment, Thurston rated his effort in Game Two one of the worst performances of his 23-game Origin career. Such was his abject disappointment, Thurston put his game under the microscope and decided to modify his playing style after an inconsistent start to the season at five-eighth for the Cowboys.

Against the Broncos on Friday night, Thurston said he deliberately varied his game. He alternated between first and second receiver to keep the opposition guessing and prevent Brisbane's left and right-edge defenders rushing up on him in a fixed role at five-eighth.

Thurston's transition from halfback to five-eighth this season was expected to be simple and seamless, but the two-time Dally M winner admits succeeding Lockyer at Test and Origin level has been more onerous than he imagined.

Under pressure to lead the Maroons to a seventh consecutive series victory in Origin III on July 4, Thurston hopes his display against the Broncos is the blueprint to dominate the Blues without Lockyer in the Suncorp decider.

"That game the other night (Origin II) was one of my worst in a Queensland jumper," Thurston said. "To be honest, I've been disappointed with my performances in general over the past month.

"I've just been making uncharacteristic errors. I did it in Origin (II).

"It is a different role (at five-eighth). It's not easy replacing Locky. I've learned just how good he was, how he controlled a game under pressure.

"I'm still learning that. I was lucky to be alongside Locky (as Queensland and Australian halfback) and that certainly helped my career no doubt, but to play No.6 without him there is a bit different.

"I really needed to turn things around. I wanted to prove a point (on Friday night against the Broncos). I wanted to prove something to myself and to my teammates. I felt I did that."

Largely ineffective against the Blues - he made just three runs for 22 metres - Thurston made a slight but critical modification to his game on Friday night.

He decided to run often and play more direct. He appeared more regularly at first receiver, which gave Thurston early ball and less time for the Broncos defence to rush up and limit his playmaking time.

The results were an ominous portent for NSW: six tackle busts, one line break, one line-break assist and 122m from 11 runs.

"I've had to adjust to the way the teams are defending against me at five-eighth," Thurston said. "It's been a rollercoaster ride, I've had some good performances and then not so good, but that was much better.

"I don't know if I ever feel comfortable in Origin, but the fear of failure drives me."

The significance of this year's Origin decider is not lost on Thurston. On the same stage last year at Suncorp Stadium, Thurston was famously brought out in a wheelchair to celebrate Lockyer's farewell after he hyperextended his knee in the second half of Queensland's 34-24 victory.

"I don't know if I was the hero that night, all I remember being dazed from sucking on the green whistle (painkilling device)," Thurston said with a laugh. "Once Locky was going to hang up the boots I had a think about my game and how when Locky would sit at the back and when he saw an opportunity, he'd get in there.

"I'd like to play that way too."