Brisbane prop Haas had come under fire leading into game two for his failure to translate his all-conquering NRL form into Origin performances for the Blues.
But Haas showed no self preservation across a 53-minute performance in Melbourne on Wednesday, chalking up 166m metres across 19 carries at the MCG as NSW squared the series with a 38-18 win.
Leniu said the Broncos forward's efforts were all the more impressive when considering the off-field toll he was dealing with.
Haas' father Gregor was recently arrested in the Philippines on drug-trafficking allegations but the prop showed maturity to stand tall for the Blues.
"Payne was unbelievable, he's such an inspiration to so many front-rowers," Leniu said.
"He's still so young and to see him competing the way he does ... everything with his family going through the media.
"To put that aside and turn up for this game is so inspiring, I'm grateful that I get to play alongside him."
The ability of Haas to smash through the Maroons pack allowed Leniu to cause havoc when he was injected into the game after the half-hour mark.
On one of his first carries the fleet-footed Leniu charged through a tackle from Harry Grant and Reuben Cotter, making 30 metres up field to lay the platform for NSW to take a 34-0 lead in at halftime.
Harry Grant watching on as Spencer Leniu drives the Blues up field at the MCG. (Joel Carrett/AAP PHOTOS)
"Breaking through the line is a bonus, I was just like 'Please don't tear my hamstrings' it was my first carry so I wasn't as warm," Leniu said.
"I was like, 'What the heck is going on here?'
"I was trying to come out and make a difference when I came on.
"Seeing Payne, 'Muzz' (Cameron Murray) do the business in the first 30 minutes was an inspiration for me to go out there and make a difference."
Leniu is keen to continue his flourishing combination with Haas in the game three decider at Suncorp Stadium in Brisbane on July 17.
The Sydney Roosters forward won't settle for anything less than a win.
"What a story it's going to be (when we win)," Leniu said.
"Our backs were against the wall in this game and it'll be no different in Suncorp.
"It'll be an against-all-odds mentality and what gives me confidence is the brotherhood we have ... in enemy territory it will make the story that much sweeter."
