The 24-year-old half landed eight goals from eight attempts on Wednesday and took control of the match when the Maroons trailed 10-2, outplaying opposite number Nathan Cleary in a 44-24 win to take the State of Origin series to a decider in Brisbane.
Walker played as a solitary half in attack when five-eighth Cameron Munster was off the field for 15 minutes with an HIA -- and he stood up with class.
The naysayers who reckoned Walker was too small or too flashy for Origin have been shown up.
"There were question marks on him, mainly around his defence and whether his style of play would stand up at this level," former Maroons skipper Smith told AAP.
"I think he has answered all his critics with his first two Origin performances.
"Everyone has spoken about game one and how Queensland win if Kalyn Ponga stays on the field. I tell you, if Queensland win game one, Sam Walker wins man of the match in that game too.
"It looks like Sam has played 20 Origins, not two. He is playing with composure and he understands his role he has been asked to go out and play."
A second half play where he caught the ball from a scrum and without looking flipped it up for Kalyn Ponga to collect and set up a try for winger Selwyn Cobbo was magic.
"What works for him in the modern game is he has no fear," Smith said.
"He doesn't look at an opportunity as a risk. He looks at it as an opportunity to go and do something positive for the team.
"We see that through his short kicking and his options whether to spread the ball wide, turn the ball inside or have a little dart. It's really good to watch."
Walker said it was "really special" to win the match and to be so influential in the result as he explained the scrum play that led to the Cobbo try.
"We put the last tough loss behind us and came out and performed like we said we would," Walker told AAP.
"I practice every skill over and over again and I am confident in my passing game. I was lucky to throw it up there and KP (Ponga) was fast enough to catch the ball.
"KP was unbelievable and we have built a really combination because we both play off-the-cuff. Give him an ounce of room and he will create something out of nothing."
Queensland coach Billy Slater hailed Walker's ability to handle the Origin cauldron.
Slater didn't even realise the Sydney Roosters halfback had been awarded man-of-the-match honours when speaking post-game.
"He's so humble and so respectful but oozes confidence in his own ability," the Maroons and Melbourne Storm legend said of Walker.
"The more time that I've spent with Sam, the more I understand the greatness of his game.
"He handles pressure situations.
"When you think about that try off the scrum, he's in a pressure situation and he handles it with calmness and with skill.
"He's the last one out on the field with his working on different parts of his game."
10°C