"I'm not sure if it was the bye because the last time we came off a week off we came out pretty good, so we'll have to have a look at all that."
Pressed on what signs gave him the impression his side were not completely switched on, McFadden put it down to a gut feeling.
"Just a general feel, you can feel it. Usually when your players are switched on you just can feel it.
"They don't go away, the Broncos. They're a real competitive side so we're very happy with the win."
Coming off their line, the Warriors are usually well served by their imposing outside backs, but Manu Vatuvei, Konrad Hurrell and Sam Tomkins were all guilty of coughing up possession, while the normally reliable 19-year-old wing David Fusitu'a made two glaring errors, which epitomised the team's off-colour display.
"I guess that's why we didn't play that well. We just put ourselves under too much pressure and we never really put the opposition under much pressure so that was certainly a concerning thing that we'll have to work on," McFadden said.
One positive sign was the improving form of replacement back-rower Feleti Mateo, whose timely arrival on the park sparked the Warriors attack into action when he delivered a nice ball to put Ben Henry away for their first try.
"I thought that was his best game," McFadden said. "He obviously provided some spark for us because we were lacking that at some points in the game."