The defending men's champions turned a 10-point deficit into a 15-point lead either side of half-time on Tuesday, then held their nerve after Spain got within four points to begin the final term.

Gasol brothers Marc and Pau played just 16 minutes between them, but Spain's other forwards were in command until Durant (29 points) lifted and his team followed to offset point guard Ricky Rubio's 38 points.

"We started making shots there in the second quarter," Durant said.

"Once we see that ball going into the rim, that put all of us at ease.

"I like how we played in that second quarter, from the end of the second quarter all the way to finish the game, and that's how we're going to need to play going forward."

Chasing a maiden international medal, Australia play Argentina later on Tuesday for a place in the final four.

Slovenia beat Germany earlier on Tuesday while France play Italy in the other quarter-final.

The United States finished seventh in the 2019 World Cup and, after losing warm-up games to Nigeria and Australia, began their Tokyo campaign with a loss to France.

But they have since settled into the more physical FIBA style of play, benefiting from the addition of Phoenix's Devin Booker (nine points, nine rebounds, five assists) and Milwaukee's Jrue Holiday (12 points, five assists) from their respective NBA Finals campaigns.

"We're in a good spot right now; guys are starting to understand their roles and just get more comfortable within the team," Durant said.

"In this setting it's always hard to get your footing as an individual player because you don't want to step on toes.

"I love how we stuck with it throughout this whole period of time and guys started figuring out what we need to do.

"You've just got to finish it (now we're in the semi-finals). We're supposed to be here. For us it's about getting a gold."

Australian Associated Press