Despite reaching the quarter finals after salvaging a 14-all draw against Scotland in the group stages of the tournament, the winless Samoan side were embroiled with backlash after a string of disappointing performances and talk their talk of players – including Leilua – returning to their NRL clubs in the pre-season overweight.
One of the more experienced leaders in the line-up, Leilua told NRL.com coach Matt Parish identified the fixture as a chance to build depth for the nation.
"They're the future for our team," Leilua said.
"I'm one of the oldest in the team but I used to be one of the young bucks not too long ago.
"This is a good time so we can plan ahead for the next World Cup and hopefully go better. We owe it to our country to be better."
One player hopeful of a final spot is Leilua's younger brother Luciano, a back-rower who has played five games for the high-flying Dragons this season.
Leilua was as hard on his brother's chances of a debut as he was going up against him in the backyard as a child, not giving anything away on his sibling's chances.
"I know he's proud of himself to be a part of the squad and I'm proud of him but at the same time he's got to prove himself to me that he's got to play first grade," Leilua said.
"He's playing some good footy at the Dragons but has been in and out of their top side. I'm not sure if he's ready but hopefully I can be next to him when he does."
Meanwhile, Tongan debutants and South Sydney teammates Robert Jennings and Junior Tatola were soaking up the experience of mingling with some of the game's best in the lead-up to the clash, with the youngest Jennings brother getting some tips from experienced older brother Michael.
"Michael said it will be the best week of my life," Jennings said.
"Junior and I will soak as much experience as we can and take that back to South Sydney. It's a massive achievement for me. I want to cherish these moments and make the most of it, especially alongside my brother.
"Playing for your heritage, I've always dreamt of. It will be emotional on Saturday but I'll try and hold that in."