"I know how important the World Cup is for our country," said former captain Cahill, who played at four tournaments.

Costa Rica face New Zealand in Doha on Tuesday for the final World Cup spot.

Australia finished third in the Asian qualifying groups behind Saudi Arabia and Japan, who went directly into the main draw, and defeated the United Arab Emirates to reach the inter-confederation play-offs.

Cahill won 108 caps for Australia and is the country's all-time leading scored with 50 goals, including their first one at a men's World Cup in 2006.

"I think it's going to be difficult for Australia," said the former Everton midfielder who is now chief sports officer at Aspire Academy in Qatar.

"It's never easy, but in the end, it comes down to preparation, and whether you've done everything in your power to prepare and be mentally and physically fit for the World Cup.

"Qualifying will mean everything, particularly after the pandemic, but qualification is not a given. Being at the World Cup is ultimately what you play for."

Australia or Peru will join Group D alongside holders France, Denmark and Tunisia, while Costa Rica or New Zealand will go into Group E alongside Spain, Germany and Japan.

The tournament begins on 21 November, with the final taking place in Doha on 18 December.