SHANGHAI — The first big celebratory reaction from the U.S. bench in this World Cup came just a couple of minutes after tipoff, when Myles Turner blocked a shot at the rim. And with that, the tone was set.

There is an emphasis on defense with this U.S. team, and it was evident from the outset of its Group E opener on Sunday. Donovan Mitchell scored 16 points to lead a balanced scoring night, and the Americans steadily pulled away to beat the Czech Republic 88-67 to begin their quest for a third consecutive World Cup title.

“That’s got to be our calling card,” U.S. coach Gregg Popovich said. “We’re going to try to execute better and better as time goes on, but defensively we’ve got to put our money there. It’s what we have to be about to have an opportunity.”

Harrison Barnes added 14 points, Kemba Walker scored 13 and Jayson Tatum finished with 10 for the Americans. Turner had seven rebounds and a pair of blocked shots.

“As long as we win, that’s all that matters,” Tatum said.

Tomas Satoransky, the former Washington forward who was traded to Chicago over the summer, led the Czechs with 17 points.

While the Americans’ 78-game winning streak in international games with NBA players ended last month with a loss at Australia, their long winning streak in major tournaments continued. It’s now at 54 games, starting with the bronze-medal game of the 2006 world championships and continuing with gold-medal runs at the 2007 FIBA Americas, 2008 Olympics, 2010 world championships, 2012 Olympics, 2014 World Cup and 2016 Olympics.

“We did a lot of good things,” Mitchell said. “We guarded it well. We’ve got a lot of things we can definitely work on, and I think this is a good start to the tournament.”

The Czechs scored the first four points of the fourth quarter to get within 66-52, but the Americans weren’t threatened. Walker made a 3-pointer to stop the mini-run, found Mitchell in the corner for another 3-pointer that made it 72-52 about a minute later and the outcome was academic from there.

The Czechs had their highlight run early for a quick 11-7 lead, and the couple thousand of their fans in Shanghai — most of them wearing either white or blue team jerseys, with a few Wizards jerseys for Satoransky mixed in there — were roaring.

It didn’t last long.

After a 9-0 run by the Czechs, order was quickly restored. The Americans scored the next 10 points, kick-starting what became a 29-9 run in all, and led by as many as 16 before going into the half with a 43-29 edge.

And it was defense that carried the Americans. Over a 10-minute stretch of the half, the Czechs went 4 for 20 with seven turnovers.

“The chemistry is building,” Barnes said. “Looking forward to it continuing to build.”