The 28-year-old defender enjoyed an outstanding World Cup in Germany before his stoppage-time foul on Fabio Grosso gave Italy the penalty that earned them a 1-0 victory and a place in the quarter-finals.

"Lucas has become a real leader," Arnold told reporters after arriving back in Sydney on Friday.

"Lucas is a leader in the side and he stood up. The bigger the game, the bigger Lucas Neill gets. He keeps going to another level."

Viduka and former captain Craig Moore are likely to consider their international futures after the second-round exit in the nation's first World Cup appearance for 32 years, and Arnold believes Neill has the class to step up.

"Lucas was probably the best player over the tournament for Australia and one of the form defenders of the whole World Cup," he said.

Neill himself said it would take time to recover fully from the incident.

A graduate of the Australian Institute of Sport, Neill is out of contract with Premier League club Blackburn Rovers and has been linked with a move to Barcelona, where assistant Socceroos coach Johan Neeskens has joined Frank Rijkaard's backroom team.

"The last few days have been an emotional rollercoaster for me and the whole team," Neill said in a statement.

"To know that so many people have taken the time to personally send me a message of support has helped soften the blow of the result, but it will still take some time to get over."