– While her U.S. teammates struggled against France, Sue Bird found it even more difficult to watch. The veteran point guard, who had started every game in the past three Olympics, sat out with a sprained knee Thursday and agonized throughout the first half of her team’s semifinal.

“It was really hard,’’ said Bird, whose 132 games with the national team are the most on the current roster. “We were a little out of sorts. I felt like I could help in that department.’’

Bird might be able to assist the U.S. in Saturday’s gold medal game against Spain, a 68-54 winner over Serbia, if her right knee continues to improve. Thursday at Carioca Arena 1, her team was on its own, and it finally adapted in the third quarter of an 86-67 victory. France’s physical play kept the game close until the U.S. defense asserted itself, holding France to eight points in the third quarter.

Bird was injured during Tuesday’s quarterfinal victory over Japan. There is no structural damage, and though she said she felt “dramatically better’’ on Thursday, the Lynx’s Seimone Augustus started in her place.

The U.S. made it to the Olympic final for the sixth consecutive time and ran its Olympic winning streak to 48 games. But it sorely missed Bird’s ability to keep its offense running smoothly. The Americans had been averaging 105 points and 30 assists per game; Thursday, they finished with 86 points and 15 assists.

“There were a lot of different things we had to adjust on the fly,’’ coach Geno Auriemma said. “We’re better off for it. We’re better prepared for Saturday’s game, having gone through [Thursday’s].

“We’re a much better team when Sue is on the floor. But we’ve been able to respond to whatever different things have come up. To be considered a great team, you have to win the whole thing, and you have to have the ability to win a lot of different ways.’’

The margin of victory in the semifinal was the thinnest for the U.S. in the tournament. It had won its six previous games by an average of 41.7 points, thanks in part to Bird’s team-high 30 assists and the court savvy she has brought to the Olympic team since 2004.

France, which lost to the U.S. in the 2012 gold medal game, used its muscle to disrupt the Americans’ offense as they tried to adapt to Bird’s absence. The U.S. took a 10-9 lead with 4 minutes, 51 seconds left in the first quarter on a Maya Moore jumper, and it never trailed again. But it couldn’t get any distance on the French, who kept the margin to single digits for most of the half.

At halftime, the U.S. lead was just 40-36. Bird did her best to give her team a spark without being on the floor, chattering on the bench and in the locker room at halftime.

“France did a good job in the first half of taking things away,’’ said Lynx guard Lindsay Whalen, who finished with five points. “Sue was telling us, ‘Just stick with it. Keep running our sets. It’s a long game.’ We all had to buckle down and make it happen.’’

The U.S. outscored France 25-8 in the third quarter, using a much tougher defense to force eight turnovers. Guard Diana Taurasi adjusted her role to distribute the ball more and finished with a team-high 18 points and four assists.

Moore added 15 points, Augustus made five of six field-goal attempts to finish with 10, and each also had three assists. Lynx teammate Sylvia Fowles also had a strong game with 12 points and a team-high nine rebounds.

The U.S. thrashed Spain 103-63 during the group-play stage of the tournament. Spain made the Olympic final for the first time, while the U.S. will play for its sixth consecutive Olympic gold medal.

Bird will test her knee at practice Friday. She insisted she will not play if she is not completely healthy, but she made it clear she doesn’t want to be a spectator again.

“I’m hoping for the best,’’ she said. “If I can play, I’m definitely going to play.’’