SHENZHEN, China -- In the Rio Olympics three years ago, Team USA averaged 101 points a game with Kevin Durant, Kyrie Irving and Carmelo Anthony leading an electric offense.

In the 2014 World Cup in Spain, the Americans averaged 105 points with Irving, James Harden, Steph Curry and Klay Thompson combining to shoot a sizzling 46% on 3-pointers.

Back in 2012 in the London Olympics, an absolutely loaded Team USA with Kobe Bryant, LeBron James, Durant, Anthony and Harden averaged an incredible 116 points in each 40-minute game.

That firepower was how the U.S. dominated those events, bludgeoning the opposition with scoring. But in the 2019 FIBA World Cup, that hasn't been the case at all.

The Americans are a perfect 4-0 after their quality victory over Greece on Saturday night and are all but assured a spot in the quarterfinals that begin Wednesday. A victory over Brazil on Monday night would clinch the top spot in their group and a more favorable matchup when the knockout round starts.

So they're getting the job done. But the days of offense to spare are in the past for now.

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Ten days into the tournament, the U.S. is averaging just 87 points per game, only eighth best in the 32-team field. Frankly, it's remarkable that the team ranks as high as that, with a woeful 20th in field goal percentage at just 42.6% and 18th in 3-point percentage at 32.8%. With the closer 3-point line in FIBA play, that is a disappointing number to say the least.

The opposition is about to get much better, so it stands to reason Team USA is going to have to find some more offense at some point if it's going to win its third straight cup.

"We obviously want to shoot better, we have to get better," said Joe Harris, who is one of the few bright shooting spots, as he has made 58% of his 3-pointers in the four games. "Sometimes shooting is contagious, the rhythm hasn't necessarily been there."

Day after day in China, coach Gregg Popovich and various players have talked about the importance of defense with this combination of players. And they're playing it, they're active and they pressure the ball and they rotate and they cheer for each other. The Americans have been one of the World Cup's best defensive teams, giving up just 64 points a game on a very impressive 36% shooting.

You could go back to each of those past three offense-laden teams and point out how much better the Team USA defense has been with this group. For example, in Rio the Americans gave up 78 points a game. Nonetheless, the shaky offensive output is worrisome.

"The defense is ahead of the offense for sure, but that's expected with 12 guys who have never played together before," Popovich said. "Each day that we have we hope that our execution can get better and better and we learn as coaches what's best for these guys."

Kemba Walker has been the only consistent option, averaging 14.8 points and shooting 40% from 3-point range. Donovan Mitchell, who is being counted on for offense, is shooting just 44% overall and has gone through cold spells. Before he got hurt, Jayson Tatum was shooting just 32 percent. Khris Middleton, whose role for this team is to be a scorer off the bench, is shooting 39%.

"When you look at past USA teams, scoring has not been an issue. There's been a lot of talent," said Harrison Barnes, who was on the 2016 team. "For us, defense is how we're going to stay in games and compete and that's what has been carrying us right now."

Maybe "right now" lasts another week -- that's all they need. But it's a little bit of an uncomfortable position that the team isn't used to, worrying about points. There are times when the U.S. is generating good shots and missing. But the more the missed shots pile up, the more the opposition makes it harder on Team USA.

Over the past three games the Americans have seen healthy doses of zone defense as opponents look to cut off Walker's and Mitchell's driving ability. With that team 3-point percentage so low, it's a guarantee that will continue. The players aren't used to seeing zone, and a few weeks of practice against it doesn't break old habits.

"Teams are going to play zone against us and we have to be confident, we can't be reactive, we've got to be aggressive hunting shots," Harris said. "I think we'll inch our way there."