Penrith's third title will go down as the Panthers' gutsiest, after a gruelling finals campaign ended in a 14-12 grind over South Sydney.

Cleary admitted he'd endured a sleepless night on match-eve, fearing the repercussions of his club's mounting injury toll and the fact it could bring his team undone.

"There was at least five who shouldn't have been playing today," coach Cleary admitted.

"It was a calculated risk on a lot of boys. I woke up at 2am (Saturday) morning and couldn't get back to sleep.

"Thinking three or four of them could have been gone by 10 mins. They just refused not to play."

James Fisher-Harris battled a knee injury in grand final week and Moses Leota a calf strain, while Nathan Cleary's shoulder issues have been well documented before his Clive Churchill Medal win.

Brian To'o has also fought lingering syndesmosis issues throughout the finals, before totalling 235 metres to continually start Penrith's sets off in a powerful fashion in the final.

But it was the braveness of Edwards that is likely to be most remembered.

Edwards spent the majority of grand final week on crutches as he dealt with a broken foot, before running 217 metres with ball in hand and making a crucial last-ditch tackle on Cameron Murray late.

"Dyl has had a broken foot for a month, has not trained," Ivan Cleary said.

"He walked around on crutches every week and then goes out and plays. I don't understand how it happens, but it sums up the bond.

"We have had a lot of guys play through injury all season. Bizza (To'o), Tyrone May.

"It just created that culture that no one wanted to be the one who put their hand up and say I don't want to play. It was incredible."

Penrith's injury toll throughout the finals is made even more remarkable by the fact they had to do it the hard way after losing in week one to the Rabbitohs.

Their tight wins in week two and week three were played at an intensity greater than State of Origin with high ball-in-play time.

They were also forced to make more tackles than any other team over the past four months.

But they were able to control Sunday's grand final with Nathan Cleary barely troubled while kicking, and rarely coughing up the ball at their own end.

"I can't wrap them enough, the courage these boys have shown," Ivan Cleary said.

"We really couldn't train the last three weeks as a team with so many guys not training.

"Lucky the games were so hard each week, that was enough training.

"It's purely on courage these boys have won."

Australian Associated Press