Team USA continued its preparations for the 2019 World Cup early Saturday morning with a surprising 98-94 loss to Australia. This was the team's second matchup against Australia this week, and the action once again took place at Marvel Stadium in Melbourne, where 52,079 people packed in to make history as the largest crowd to ever watch a basketball game in the country.

The Australian fans also saw history as well, as the Aussies beat Team USA for the first time ever, and handed the Americans their first loss in 13 years, ending a 78-game winning streak that stretched back to 2006.

In a bit of irony, it was Patty Mills who closed out Team USA, pouring in 13 of his game-high 30 points in the fourth quarter. During the final three minutes, Mills was the only player to score for the Australians, hitting a number of tough shots to secure the victory. Mills, of course, plays for the San Antonio Spurs, who are coached by Team USA head coach Gregg Popovich. 

"They played well. That's a really good team over there, man," Kemba Walker said after the loss. "We beat them the first night, they came out, they wanted it more than us. Lesson learned for us."

Walker once again led Team USA in scoring, finishing with 22 points in defeat. Harrison Barnes added 20 points, while Donovan Mitchell chipped in 12. No other Team USA players scored in double figures.

Next up for Team USA is Canada on Monday. That game will once again be played in Australia, though the action will shift to Sydney.  Here are a few key takeaways from Team USA's loss:

A work in progress

Gregg Popovich switched things up with the starting lineup on Saturday, sending out Marcus Smart, Donovan Mitchell, Khris Middleton, Harrison Barnes and Myles Turner. Only two of those players -- Mitchell and Turner -- started the last game. In addition, everyone got into the game for decent stretches, save for Kyle Kuzma, who was out with a sore ankle. If the fluid roster situation didn't make it clear that this team is still a work in progress, the result certainly did. 

Team USA struggled to deal with the Australians' aggressive defense and was often discombobulated on offense. It registered just 11 assists on 30 field goals, often resorting to iso-ball to try and get a look. A lack of size and cohesiveness on the defensive end was also evident, as the team was out-rebounded by a wide margin and gave up 46 points in the paint. This was just Team USA's third game together, so it's not much of a surprise that the players are still trying to figure each other out; the problem for this group is they don't have the top-tier talent to make those sort of issues irrelevant.

Walker establishing himself

The only All-NBA player on this Team USA roster is Kemba Walker, and that's been obvious during the two games in Australia. Walker finished with a team-high 23 points in the first game against the Boomers, then followed that up with 22 points on Saturday to once again lead the way. He wasn't a part of the starting lineup for this game, as Gregg Popovich shook things up, but after a sub-par first half, Walker was back out there with the starters in the second half. In a game in which Team USA struggled to find its offense at times, Walker was often the one to bail them out. In the end he wasn't able to do enough to lead the Americans to victory, but he has established himself as one of the clear leaders of this team.

Exhibition? What exhibition? 

This was billed as an exhibition game, but no one told the players or fans -- especially not on the Australian side. The Boomers, as they're called, were ready to play from the opening whistle, eager to get revenge for the 16-point defeat Team USA handed them just a few days earlier. Using some aggressive defense that often included picking up full-court, Australia frustrated Team USA on that end. On offense, their veteran NBA players -- Joe Ingles, Andrew Bogut and Patty Mills -- stepped up with big performances that covered all aspects of the game. 

If Team USA wasn't up for the action in the first half, it was dragged into it in the second by an Aussie team that wouldn't go away. By the fourth quarter, it felt like a knockout stage game late in the World Cup, with pride kicking in for both sides and an amped up crowd increasing the atmosphere. Those who stayed up to watch the game that started at midnight EDT Saturday and went into the early morning hours in America were rewarded for their endeavor with an exciting contest.