SHANGHAI -- Kemba Walker and Jayson Tatum are probably going to win a lot of games with the Boston Celtics over the next few years. On Sunday, they combined to play important roles in their first consequential win together as Team USA opened the FIBA World Cup with an 88-67 victory over the Czech Republic.

Tatum and Walker combined for 20 points in the first half as the U.S. got some separation after a bit of a sluggish start. The Americans played only five exhibition games -- some of their competition in the tournament played more than 10 -- and had revolving lineups and personnel, which made the start of pool play a bit of a soft open for this roster.

But Tatum has shot the ball well since the group got together for training camp a month ago in Las Vegas, and he drilled two 3-pointers out of the gate to keep that going. Tatum finished with 10 points.

"Playing together so much together now [with Walker] has built up chemistry for the season," Tatum said. "Hopefully there's good things to come for the future."

Meanwhile, the Czechs' game plan was to attack the smaller Walker with their best player, Tomas Satoransky, who has roughly 6 inches on him. Time after time, Satoransky went to the post to try to push around Walker in the first half.

The Bulls gave Satoransky a three-year, $30 million deal over the summer, in part because of his ball skills at his size. But then the Celtics gave Walker $140 million because he's a star who is used to playing against size.

Walker held his own, poking the ball away several times and not being afraid to foul when he lost leverage.

"Oh yeah, they came after me," said Walker, who had 13 points. "It's a different game than the NBA; it's a lot more physical. We're Team USA, we're going to get everybody's best shot, especially physically. Teams are going to be tough against us. We just have to hold our composure and be tough and play through everything."

Walker also made an impact at the other end, where his quickness busted the overmatched Czech perimeter repeatedly. His stop-and-go actions and quick side-to-side moves drew "oohs" and "aahs" from the capacity crowd at the Oriental Sports Center.

Kemba Walker finished with 13 points to help pace Team USA to a win in its opening game of the FIBA World Cup. Wu Hong/EPA

Walker's performance was part of a strong U.S. defensive effort, which coach Gregg Popovich is hoping will be the bedrock of this team's run toward a third consecutive World Cup title. The Czechs shot only 35 percent in the first half as the Americans blocked five shots and pressured them out of their offense.

Popovich wants energy from his defense and he kept players fresh, playing 10 of them in the first quarter alone. After giving up 98 points in their letdown loss to Australia a week ago, Team USA has held its last two opponents to less than 70 points (including its final warm-up game against Canada).

"Happy is not a word that coaches employ, because we're sick puppies and probably never happy," Popovich said. "But defense has to be our calling card. We've got to put our money there. All in all, it's getting better."

In the second half, Donovan Mitchell (16 points) and Harrison Barnes (14 points) provided much of the offensive punch as Team USA expanded the lead and were able to get their first win without much stress.

"We did a lot of good things," Mitchell said. "This was definitely a good start."

Star of the game: Walker was 6-of-8 from the field for 13 points along with four assists and a steal.

Stat of the game: After going just 2-of-14 from 3-point range in their last exhibition game against Canada, the Americans went 10-of-26 against the Czech Republic.

Up next: The Americans play their second of three pool games against Turkey on Tuesday (ESPN+, 8:30 am ET). This is a rematch of the 2010 World Championship Game, and the Turks are likely the toughest competition in this pool for Team USA. They have three current NBA players in Cedi Osman, Ersan Ilyasova and Furkan Korkmaz, as well as former NBA player Semih Erden. Ilyasova had 19 points and made five 3-pointers in Turkey's 19-point win over Japan on Sunday night.