Speaking on Saturday's episode of FanDuel's Coaches Corner, Arena, Bob Bradley and Gregg Berhalter praised the Americans' physicality and first-half display, while noting that Pulisic's absence as he recovers from a calf injury left them short on creativity in the final third.
"I think I'm probably going to be a little different than Bob and Gregg, but I don't think the United States played a particularly strong game," said Arena, who led the U.S. to the 2002 World Cup quarter-finals. "A good solid first half. Second half, not too good."
Arena said Pulisic's return was a major issue for the squad as the level of competition rises.
"That's a big question mark for the U.S. team, how they can get Christian back on the field because they certainly miss him in the attack and the competition is going to get better," Arena said.
Atletic Americans
Bradley, who coached the U.S. when they won their World Cup group in 2010, said Pulisic's absence changed the team but praised the Americans' agility and strength.
"We miss his creativity and his dribbling," Bradley said. "But we're a really athletic team and for the second game in a row, our athleticism really pushed the opponent."
Berhalter, who led the U.S. to the round of 16 at the 2022 World Cup, said Australia struggled with their opponents' physical approach.
"Australia are a physical team, a tough team, and they couldn't deal with what we were giving them physically," Berhalter said. "It wasn't the best performance over 90 minutes, but it was certainly enough."
Berhalter also praised Folarin Balogun, saying the forward had been "sensational" and "terrorises the defence".
The victory marked the United States' first shutout in 10 games, and Bradley said that was important after the team conceded against Paraguay. But he added that Australia did not fully test the U.S. defence.
"The big questions haven't been put on display yet," Bradley said.
Turkey test
The U.S. next face Turkey, who have lost their first two matches and are eliminated. Arena said Turkey may be the group's strongest technical team and warned they would still have pride to play for.
Turkey coach Vincenzo Montella would need to lift a distraught squad, Bradley said, while Arena compared the situation to 2002, when already-eliminated Poland thrashed the U.S. 3-1 in the final group game.
"They wanted to prove they had pride in themselves as a team," Arena said.
The coaches also noted a potentially worrying decline in intensity after halftime.
"We seem to drop our energy level considerably in the second half," Berhalter said. "Are we getting to a point where we're fatigued?"
Arena said tougher opponents would provide a clearer indicator of the U.S. team's strength.
"We are going to find out a lot more about our team in the round of 32 and then the round of 16," he said.