Smith, who made his Storm debut in 2002, hits 300 NRL games today and has at least two or three more seasons in him, while 28-year-old Mannering is within 50 games of Stacey Jones' all-time mark for the Warriors (277).
But what stands out most is their durability over a long period, during which they have barely missed a game - or minute - for their club.
"They are very similar in terms of toughness and their ability to play through pain from week to week," said Warriors coach Andrew McFadden. "It is amazing that they can stay on the field. Simon - and probably Cameron as well - can put themselves through a lot, keep going and still produce the quality."
The numbers are staggering. Over the past decade, Smith has averaged 22.7 NRL games a season and never played less than 20 in a year.
Mannering has contributed 22 games a campaign during those 10 years, with his lowest output being 17, in his first full season (2006).
Across that time, Smith has averaged 77.5 minutes per game, Mannering 77.1.
"There's no secret as to why [Smith and Mannering] have been so successful ... it's all those attributes that they have," said Nathan Friend, who has played several seasons with both men. "They are probably on the higher scale of tough and play through a lot of pain that you don't see. They've also had a bit of luck not to receive a big knock."
The duo have set a new bar in terms of fitness, willpower and recovery. Since 2006, Smith has played 36 Origin games but rarely lets it affect his club form. And before the stand-alone Anzac test window came into affect, Smith sometimes turned out for the Storm less than 48 hours after playing for the Kangaroos. Meanwhile, with Kiwis games and tours, Mannering played virtually non-stop for six seasons between 2006 and 2011.
Mannering has carried an injury for the past month that only the club doctor was privy to, with McFadden hearing about it only last weekend. The coach also recalls a 2014 game, when Mannering played on with a knock that might have grounded others.
"He hyper-extended his elbow and it was quite a significant one," said McFadden. "But he strapped it up pretty quickly and made another 20-30 tackles after that. For some guys, that would be day over. He carried it for another six or seven weeks. He doesn't like to make a fuss of things ... he knows that can distract team-mates. Generally, the way [Smith and Mannering] can produce such quality on the field - under duress - that is what stands them out above a lot of people."
And the work rate has never dimmed. Over the past decade, Mannering has averaged almost 29 tackles a game, with an effective tackle percentage of 90 per cent. Smith has made almost 38 tackles a match, with an effective tackle percentage close to 92 per cent.
They are also not dissimilar in terms of personality.
"Cameron's a fairly quiet guy, with a very dry sense of humour," said Friend. "There was always minimal words with Cam, but what he said made sense. Simon also tends to let his actions do the talking."
Mannering, who has faced Smith on the pitch more than 50 times, is an unabashed admirer.
"He's a key guy for every team ... Melbourne, Queensland, Australia," said Mannering. "He probably doesn't get the credit he deserves, especially for what he does defensively."
Their contributions will be key today. Smith often controls the Storm on attack, and can slow the ruck defensively.
Mannering is the king of the 'one percenters' and will need to make the vital tackles in the middle throughout the 80 minutes. Despite the recent good form of the Warriors, the likely absence of Konrad Hurrell (shoulder) and Ryan Hoffman (calf) today gives the Storm an edge.
"The main thing about the Storm is that they work well for each other and don't let each other down," said Friend. "If there is a cover tackle to be made, you'll probably see three or four guys in the picture. They are a well drilled side and don't get flustered. They are never really beaten."
