The 10-man Jets exposed chinks in the champions' armour on Saturday, in a performance Arnold described as uncharacteristic and symptomatic of straddling two competitions at once.

While the 2-1 loss did little to hurt Sydney's A-League advantage - now eight points - there's little room left for error in the ACL.

A 2-0 opening loss to Suwon Bluewings and 2-2 draw with Shanghai Shenhua leaves Sydney bottom of their group before home-and-away ties with J-League powerhouse and Group H leaders Kashima Antlers.

"I do believe that unintentionally the players had one eye on Wednesday night's game more than Saturday's," Arnold said.

"That's probably the challenge of the two competitions at the same time ... it was a one-off performance I've not seen in a long time.

"When you have one or two players flat there's not really a need to question anything but when you have 10, 12, 13 players flat you need to look at what you've done during the week.

"I believe the Shanghai game and Wanderers game took a lot of emotion out of the players and a hell of a lot of effort.

"Sometimes things like that happen. You suffer from it days later.

"We're recovered now ... I know we'll see the real Sydney FC tomorrow night."

Arnold was quick to deflect any pressure back onto Kashima, claiming an advantage over a squad who've had to fly internationally.

He expected Go Oiwa's side to sit back and counter-attack but had a specific game plan based on reports from assistant coach Phil Moss's recent trip to Japan.

It's anticipated Michael Zullo may return from his minor hamstring injury though Milos Ninkovic remains under a cloud after pulling up clutching his hamstring against the Jets, in what Arnold played down as a cramp.