"After the heavyweight title fight the other day, (Deontay Wilder) said 'You believe it, you speak it, you receive it'," Arnold quoted in his pre-match press conference.
It's unsurprising that the Sydney FC coach is looking elsewhere for inspiration at the moment.
Suddenly, Arnold has his back against the wall for the first time in two seasons. Sydney are reeling from a loss to 10-man Newcastle Jets in their last match. It's a loss which has some pundits, for the first time, considering Newcastle as genuine Championship contenders this season.
It doesn't make Sydney's task any easier, that they're currently fighting on two fronts.
Sydney have never beaten a J-League side, but after a loss and a draw in their opening two Asian Champions League group games, they're going to need to secure points away from home. 
"It's about belief and belief is huge in this group," Arnold said.
"Unintentionally, the players (against Newcastle) had one eye on Wednesday night because that's the challenge of the two competitions at the same time, which is new to a lot of players.
"We removed that straight after the game. It was a one-off performance that I've not seen in a long, long time."
Kashima aren't coming off the strongest form themselves, currently sitting seventh in the J-League. But the runners-up in Japan's domestic competition last season certainly have the quality to beat a "flat" Sydney at home.
"When you have one or two players flat then there's no need to question anything. But when you have 12-13 players flat you then need to look at what you've done during the week," Arnold said.
"I believe the Shanghai game and Wanderers game took a lot of emotion out of the players and hell of a lot of effort.
"You suffer from it five to nine days later with fatigue or mental fatigue but we're recovered now. Straight after the game, I addressed it.
"You can't dwell on things... and I know we'll see the real Sydney FC tomorrow night,"