"I can't remember who it was, I think it may have been Gifty [Glenn Stewart] and Stevie Matai," Horo said.
"They didn't get in my face or anything like that, but they made it clear that the club has high standards even in training.
"The coaches here are all outstanding, but the senior playing group are so experienced and have been brought up with a winning culture and that rubs off of everyone."
Only Melbourne have a better recent finals record than Manly, who have finished in the top eight every year since 2005 and won two premierships.
It's a remarkable achievement considering the club has one of the more unstable boardrooms in the NRL and lacks the huge financial clout of Sydney rivals Canterbury and Parramatta, who are backed by wealthy league clubs, and the News Limited-funded Brisbane.
Tonight's preliminary final against a South Sydney side refreshed from a week's break will present a huge test for Geoff Toovey's side - one many believe will be too big for his weary players.
After backing up from their 4-0 loss to the Sydney Roosters in an epic qualifying final clash, the Sea Eagles were out on their feet in the second half of last week's gritty 24-18 win over Cronulla.
They must now face a giant Souths pack, but Horo has warned Souths that with a grand final spot at stake, knowledge is power.
"There are a lot of boys here who have only played in winning sides," Horo said. "Matai, the Stewart boys, Matt Ballin, Jamie Lyon, Brent Kite, they've only known finals football every September.
"That's huge going into a game like this."
- AAP