Harrison Barnes describes the feeling of playing for Team USA and how the players are motivating themselves to win it all. (1:09)

ANAHEIM, Calif. -- Spain had sliced an 18-point lead to eight with four minutes remaining as Gregg Popovich watched to see how his young Team USA would respond.

Joe Harris buried a 3, Mason Plumlee stole the ball off a Ricky Rubio pass, Derrick White made a floater, and then a Kemba Walker steal led to a Jayson Tatum 3-pointer to end any threat by Spain. In its first exhibition tune-up before the FIBA World Cup, Team USA led by as many as 18 before holding off Spain late for a 90-81 win at Honda Center.

After the first two weeks of camp, USA Basketball heads to Australia on Saturday with 14 players on the roster after P.J. Tucker withdrew on Friday with a minor left ankle sprain.

Popovich will make final roster cuts to 12 later, as Team USA will play its final two exhibition games against Australia in Melbourne before facing Canada in Sydney ahead of next month's FIBA World Cup in Shanghai.

The remaining USA Basketball players are eager to prove that they all belong and are worthy after a summer that saw several of the biggest U.S. stars decide to skip the World Cup to prepare for the NBA season.

Regarding the chatter of just how good this team can be, USA forward Harrison Barnes told The Undefeated's Marc Spears, "We hear the noise. It's just about the 14 guys that we got here right now, and when we go to Australia, it's about just us, getting better, continuing to grow closer on and off the floor, and we'll go from there."

Barnes added that the team is "motivated more than anything to keep the gold standard going, by the teams that went before us, that went and won the World Cup, that went and won the Olympics multiple times. That's what we're chasing right now."

Donovan Mitchell appears poised to play a big role. He led Team USA in scoring with 13 points and four rebounds Friday. Walker had 11 points, eight assists and six rebounds, and Khris Middleton added 12 points. Against the likes of NBA players such as Marc Gasol (19 points) and Rubio (16 points, seven assists), the Americans watched Spain make 12 of 25 3-pointers but held their opponents to 40.8% shooting overall and out-rebounded them 42-20.

"A good chance to jump into the fray and see what this is all about it," Popovich said to sum up the team's first exhibition against another country. "It was like a baptism for us. A new group, players, coaches, all those sort of things. It was a real experience."

Team USA made 11 of 19 3-pointers, but Popovich was most impressed by the defensive effort. The Americans led by 13 at the break after holding Spain to 14-of-35 shooting in the first half.

"I think that we can be elite defensively," said Kyle Kuzma. "I think that is one thing we can show that people will see more in China."

Kuzma had seven points and five rebounds in 17 minutes.

It remains to be seen whom Popovich will decide to keep on the final roster for China, but the team believes its chemistry is beginning to form.

"I'm excited about everybody coming," Mitchell said. "The biggest thing for us is just jelling on and off the floor. That's going to help us. These [other international] teams have played with each other since about 12, 13 years old. So for us, we've got to be able to match their chemistry. And I think the only way to do that is to be around each other as much as possible."