MADRID (AP) — After a difficult summer, the Basketball World Cup has been pretty easy for the U.S.

No games have been close in the final minutes, and only one was even competitive entering the final period. This depleted team that was supposed to be vulnerable has instead been invincible.

The Americans believe that tough game is coming Sunday — and so does Serbia, their opponent.

“They have supreme confidence and just that expectation, I think, that they feel like they’re going to win,” U.S. guard Stephen Curry said, “and we have that same mentality as well.”

Serbia is the only team left that can stop the Americans from repeating as world champions, looking to regain a title that’s meant so much in its basketball history.

“They are great, good team, but for sure we won’t go inside the game to lose,” Serbian guard Milos Teodosic said.

The Americans were supposed to be here, though the road to the final was expected to be tougher once Kevin Durant, Kevin Love and Blake Griffin withdrew, and Paul George broke his right leg. But the opponent is a surprise.

The Serbians barely qualified for the 24-team field as the seventh-place finisher in last year’s European championship. They were only 2-3 in the group stage, advancing as the fourth and final team from the powerful Group A, but have peaked since the games became win or go home.

A 90-72 rout of previously unbeaten Greece in the round of 16 was followed by an 84-56 victory over Brazil in the quarterfinals. Then the Serbians built a huge lead and held on Friday for a 90-85 victory over France, which had beat then in the group stage and knocked out tournament co-favorite Spain in the quarters.

“They’re just playing great basketball right now and actually it’s beautiful to see. I hope I don’t see that beauty tomorrow night,” U.S. coach Mike Krzyzewski said. “But they’ve been playing lights-out basketball.”

The Americans have been more dominant, averaging 101.5 points and winning by 32.5 per game. Their last two games had single-digit margins at halftime, and yet they ended up winning both by a combined 71 points.

“I cannot say we’re going to win against the U.S, but I’m sure we’re going to give all our best and try to fight, but it’s going to be hard for sure,” said former NBA center Nenad Krstic.

The Americans have never repeated as world champions. The last team to win titles consecutively was Yugoslavia in 1998 and 2002.

Krstic remembers cheering for his country mates during the latter game, held in the United States, at a gas station with his club team that was on a bus at the time. It was the last of a record five world titles won by Yugoslavia when Serbia competed as part of that nation.

The Serbians have retained that basketball passion since competing under their own flag — Curry played on the U.S. team that lost to host Serbia in the championship game of the 2007 under-19 tournament.

“It’s tough winning silver that game, so hopefully we can be on the other side of it this time around,” Curry said.

Serbia is already guaranteed its first medal at the senior level. The Serbians — whose Olympic committee president is former NBA center Vlade Divac — finished fourth in 2010.

“It means a lot because we are a basketball country,” Krstic said. “Lots of people, whole country watch this game.”

The Americans say it’s just as important to them, especially after all the adversity they faced before the games began. USA Basketball chairman Jerry Colangelo has said a gold medal would be the sweetest one since he took over the program in 2005, since it seemed so in doubt as big name after big name passed on the trip to Spain.

“It’s everything for us,” U.S. forward James Harden said. “We came here with one thing on our mind, that’s to win the gold medal. We came this far, doing an excellent job this far in this tournament. So one more game to complete our mission.”