Run, Isaah, run: The 10km slogs and fancy dress that set up Yeo's season

"That was his thing – he wanted to do that one long run at a minimum around everything else we did," Knowles said.

"They were given stuff every day, but on top of that he had to do this one long run because he wanted to test his mind.

"I really respect that in him and I love working with him.

"In a game of footy, the best would do maybe nine-and-a-half, 10 kms. That would be like a Nathan Cleary-type game. 

"Even though it's not specific [for Yeo] – it's not stop-start, agile, change of pace, and it's not footy – but it was mentally a grind.

"He told me that he wanted to do it, so I had to make sure I encouraged it and get everything around him. It was really impressive."

For Knowles, Yeo's work ethic is reminiscent of another Dubbo product – former Bulldogs captain Andrew Ryan, who represented NSW and Australia in the back row.

Yeo was rooming with Kaide Ellis, who moved to the Dragons mid-season, and the pair motivated each other in lockdown.

"I used to wake up a little bit earlier than him, so I'd go [on the run] and then as I was walking in he'd leave and go do one," Yeo said.

"That was just our little thing on a Saturday. It wasn't much fun doing it, but you always felt better after.

"I was probably going against the Hayden Knowles schedule, so we had a little discussion about that. That was the sort of thing we were doing. It used to make me feel good, so I kept doing it.

"I just used to try to make the times a little bit better. The coaching staff did a great job of putting together programs and setting us up with gym equipment and that sort of stuff."

Asked if those sessions on his lonesome were the catalyst for a vein of form that's got him on the cusp of a premiership and NSW State of Origin selection, Yeo answered: "Yes and no".

"I was obviously sort of getting used to playing just the lock role and getting used to that work rate [at the start of the year]," he said.

"I think you're constantly evolving, constantly learning. Particularly in a position now that I've been able to settle. I'm not floating between back-row, lock, centre. I've just been able to pinpoint and stay at lock.

"I think I've still got improvement in areas in that position. I'd like to think I'll be able to keep improving and going to new levels."

Being fully fit has helped, too.

Yeo played with a busted shoulder for a chunk of 2019 but put surgery on hold until Penrith's finals hopes were dashed.

"There'd be a period in each game that it'd sort of become annoying," he said.

"By the end of the season I was probably looking forward to it just getting fixed and having the operation and going back and putting my best foot forward in pre-season.

"It was obviously annoying and that was the first time I've had something like that. I'd like to think I'd handle it better next time."

Yeo was outstanding in last Saturday's win over the Rabbitohs, setting up the match-sealing try for Dylan Edwards, and will be crucial to his team's chances against the Storm in the grand final.

Knowles has long seen the ability within the 25-year-old, who debuted in 2014 and has already chalked up 148 NRL matches.

"He's always had it, but I feel he's contributed more to be a real team man this year. Everything he's done has been for the team," he said.

"Whether it be training hard, whether it be turning up in fancy dress... He's awesome. He's a pro, he's a real pro."