There will be little time to reflect for Graham Arnold and the Socceroos after Friday's impressive start to the next phase of World Cup qualifying.

Australia thrashed a disappointing China 3-0 in Qatar to get off to the perfect start in Group B, with Awer Mabil, Martin Boyle and Mitch Duke all getting on the scoresheet at Doha's Khalifa International Stadium.

Arnold's men, however, have to quickly switch their focus towards a trip to Hanoi to face group minnows Vietnam on Tuesday.

The Vietnamese, making their debut in the third stage of World Cup qualifying, took an early lead over Saudi Arabia in Riyadh but eventually fell to a 3-1 defeat after playing most of the second-half a man down following a red card.

Arnold is almost certain to make changes to his starting XI to face the Vietnamese with in-form winger Boyle appearing to tweak a hamstring before being substituted in the second half of the win over China.

Fullback Ryan Strain is also understood to be battling a hamstring niggle.

However, midfield star Aaron Mooy could start after playing the final 20 minutes of Friday's match in his first appearance for the Socceroos in two years.

Arnold said Vietnam's advantage of playing at home has been negated by the fact there won't be a crowd in Hanoi because of COVID restrictions.

"I do believe it's an advantage for the away team to play against a home team with no crowds and there'll be no crowds in Vietnam," Arnold said.

"The most important thing for me is that we recover well from (Friday's) game.

"We get ourselves ready mentally and freshen up for the game against Vietnam and we go there and get three points."

An interested observer in Qatar was Socceroos legend Tim Cahill who watched the match from the stands, and winger Mabil said it was a particular thrill to find the back of the net in front of the country's record goalscorer.

"Growing up as a kid in Australia I'd watch all the qualifiers and Tim Cahill always delivered for the country," Mabil said.

"He set such a high standard for us to follow. It's great he was here.

"It's always a dream to score for your country so to be able to do it in front of Tim is also nice because he's done everything for the game in Australia.

"We just have to continue that and represent our country with our hearts."