"We've been consistent, we've been competing really hard and we've been in every game that we've played in the last two months.
"We're just competing and that's the key to the game."
Halfback Johnson and five-eighth Thomas Leuluai were pivotal figures as the Warriors applied unrelenting pressure to dominate the first three-quarters of the match.
The No7 controlled play on the right edge and kicked cleverly in wet conditions, repeatedly turning the visitors around and forcing five line dropouts.
"He was very good," said McFadden. "Our dominance stemmed from the way our halves were controlling the performance.
"We asked lots of questions of the opposition and to their credit they scrambled and that's what they do well. They're a gritty side and they find little ways to get back in the game."
McFadden denied there were concerns over the way the Panthers managed to fight their way back from 16-8 down with two Josh Mansour tries in the 65th and 73rd minute, and was bullish about his side's ability to hang in and overcome their highly-rated opponents.
"That's what happens," he said. "Every team has these moments in a game where the opposition pushes back.
"They come out of halftime and were pretty good but we managed to find a way to win and that's important.
"Everyone was talking about how good Penrith was going before this game. We did a good job to get the points tonight."
The result saw them move into eighth spot on the NRL ladder to sit level with the seventh-ranked Titans, Panthers (ninth) and Tigers (10th) on 22 points.
Those four teams and the 11th ranked Dragons are all jostling to claim the last places in the top eight over the closing five rounds with the out-of-sorts Broncos struggling to keep sixth position.
The Warriors will look to maintain their momentum in next Sunday's away clash with Gold Coast, who will hope to consolidate their position when they face joint competition leaders Cronulla at Robina on Monday night.
