Socceroos star Tim Cahill has rated being handed the Everton captaincy as the biggest moment in his club football career.

With regular club captain Phil Neville out with a long-term injury, the Australian midfielder has worn the captain's armband in the English Premier League side's past four matches.

"It's a massive honour and a privilege to be a captain of such a big team," Cahill told the club's website.

"It's something in my career that is probably the biggest moment for me.

"It's something I don't take lightly.

"The gaffer looks for leadership and if I have the armband or not I will always be a leader of this team."

Everton are without a win in their last six matches but Cahill is determined the team can quickly turn around their fortunes.

"I have been here a long time and we lost our way a bit in the last three weeks but now it's all about getting our heads down and just working," he said.

Everton manager David Moyes is sweating on Cahill's fitness ahead of Thursday's Europa League match against Benfica, who thrashed Everton 5-0 last month.

Cahill missed training after picking up a knock in last Saturday's 1-1 draw with Aston Villa but will receive treatment up until match time.

The fitness worries also place Cahill in some doubt for Australia's upcoming Asian Cup qualifier in Oman on November 14.