By Steve Keating

RIO DE JANEIRO (Reuters) - A ruthless United States pounded Serbia 96-66 to claim a third straight Olympic men's basketball title on Sunday, giving coach Mike Krzyzewski a golden send-off.

After scrapping to a tense three-point win over Serbia in the group round, the United States quickly removed any suspense from the rematch, surging to a 52-29 halftime lead then cruising to their 25th straight win on Olympic hardwood.

Kevin Durant led the assault, pouring in 30 points including 24 in a brilliant opening half, while DeMarcus Cousins was again a beast on the boards, pulling down 15 rebounds.

"To go home as gold medalists and leave Coach K off with another gold was one of our main goals as well," Durant told reporters. "I’m excited we got the chance to do this and play with such great players, and I’m on cloud nine right now for sure.”

The rout capped a brilliant tenure as Team USA head coach for Krzyzewski, who signs off after guiding the U.S. to three consecutive Olympic gold medals and an astounding 88-1 record in international competition.

The only blemish on "Coach K's" otherwise perfect resume is a semi-final loss to Greece at the 2006 world championships.

"For me, this (gold) ranks just like the others," Krzyzewski told reporters. "I’ve been really a lucky guy, collegiately and internationally to be part of championship teams.

"I think the way these players have felt, they’re given an opportunity to play for their country and you make the most of it."

The game was also the last for captain Carmelo Anthony, who embraced Krzyzewski on the sidelines when he was substituted in the final minutes.

U.S. basketball's only four-time Olympian, Anthony exits with three gold medals and a pack of U.S. team records.

"I think I’ve given enough to Team USA basketball," said Anthony. "As much as I’m going to miss it, I think it’s time to pass it on to some of the guys who have been on the team this year.

"So for me, I’m hanging these things up U.S. basketball-wise.”

With the victory Kyrie Irving and Klay Thompson joined one of basketball's most exclusive clubs, becoming just the eighth and ninth players to win Olympic and FIBA world championship gold and an NBA title.

The final was a classic David and Goliath matchup, with basketball superpower the United States, now winners of 15 of the 18 Olympics in which they have participated, going up against tiny Serbia, who were appearing in the Olympic tournament for the first time as an independent nation.

Serbia however also brought a considerable basketball pedigree to the gold medal game, having been part of the former Yugoslavia, once a European basketball power.

More significantly, Serbia had given the United States their biggest scare in Rio, battling the Americans right down to the final buzzer in a Group A clash that offered up at least the possibility of an intriguing final.

But the United States would not be caught off guard again, their class evident from the start.

"We played them already so we were familiar with the faces and familiar with their game," U.S. guard Paul George said. "It was about taking the fight to them and I thought we did a great job of doing that tonight."

The Americans had difficulty breaking down a determined Serb defense in the opening quarter but still ground out a 19-15 lead.

Then the U.S. shifted into top gear, blowing past the overwhelmed Serbs to open up a 23-point halftime advantage.

"They played better than us," said Serbian center Vladimir Simac. "We fought and gave it everything, playing for our people. I think we made them (proud)."

"This is a golden silver medal."

Earlier, Spain edged Australia 89-88 to take home the bronze.

(Additional reporting Chris Gallagher and Draz Jorgic. Editing by Bill Rigby, Jan Harvey and Meredith Mazzilli)