The Americans had routed Nigeria 156-73 on Thursday to set the Olympic record for most points scored in a game but a staunch Lithuania defense made sure there would be no repeat of that massive score line.
With the game still in the balance, LeBron James rode to the rescue down the stretch, and U.S. coach Mike Krzyzewski said the victory, and the way they earned it, might have been the best thing for his team.
"The game itself was incredibly important," said Krzyzewski, whose team had already clinched a spot in the quarter-finals. "First, of course, to get the win but also because every possession counted. We're not usually in that type of game.
"Winning like we did was terrific for us."
James, named the most valuable player of the NBA Finals, took the game by the scruff of the neck after the disciplined Lithuanian team ran off 10 points early in the fourth quarter to take an 82-80 lead.
James sank a three-pointer to provide a little breathing room at 90-86, then jammed through a fastbreak dunk to make it a six-point lead.
A controlled switch to his left hand allowed him to finish a layup after he was already airborne and one last basket by him finished the scoring for the Americans, who improved to 4-0 in Group A play.
Lithuanian coach Kestutis Kemzura said he could understand the U.S. team having a letdown after their previous game.
"I understand how tough it is after winning such an easy game and breaking all the records, to come and focus again to play," said Kemzura, whose team fell to 1-3.
"We executed our plan and we stayed in the game all the way."
Lithuanian Martynas Pocius, who played for Krzyzewski at Duke University, said his team's game plan was effective.
"We tried to minimize our turnovers as much as possible and stop their fastbreaks, and make them shoot contested shots over the hands and box out," said Pocius, who scored 14 points for Lithuania. "We did that for the most part.
"It's one of those games where you kind of have nothing to lose. No one expects you to win the game. We didn't want to get blown out. We wanted to stay as close as we can."
In contrast to the game against Nigeria when nearly every shot the U.S. players launched found the net, the Americans made just 44 percent, while Lithuania shot 58 percent.
James and Carmelo Anthony, who had scored 37 points in just 14 and a half minutes in their record scoring spree, shared top honours for the U.S. team with 20 points apiece.
Linas Kleiza led Lithuania with 25 points.
The performance by James was another facet of the game that pleased the U.S. coach.
"He took the game over, I thought," said Krzyzewski. "He was terrific. He just really made the plays that needed to be made offensively and defensively in the last three minutes.
"To see him respond like that in this setting was one of the positives from this game."
Russia roared back from a 20-2 deficit to beat Spain 77-74 after a crucial free throw miss by Pao Gasol, seizing the upper hand for a critical seeding advantage.
The victory between the previously unbeaten teams of Group B gave Russia (4-0) the inside track with one preliminary round left to win the group and ensure a path to a possible gold medal game against the defending United States.
The see-saw struggle came down to the last seconds.
Gasol went to the foul line for two shots with Spain trailing 75-73 and 5.3 seconds left on the clock.
After a Russia timeout to give the Los Angeles Lakers NBA All-Star time to ponder his task, Gasol hit the back rim and missed his first attempt. After making the second the world's second-ranked Spaniards trailed 75-74.
Russia's Vitaliy Fridzon was fouled immediately after the inbounds pass and made his two shots from the charity stripe for the final total. He led all scorers with 24 points.
There was still 4.8 seconds left when Spain inbounded, but the ball came to Marc Gasol in the backcourt and he was not able to set up a desperation shot for Spain (3-1).
"It was a shame I wasn't able to score the two free throws which would have put us in contention," said Pau Gasol, who had made his previous four foul shots. Spain missed only two of 19 free throws in the game.
"It was a great game," said Russia's American coach David Blatt, who credited assistant coach Dmitry Shakulin for suggesting he use a timeout to try and disturb Gasol before the key free throws.
Spain, coming back from a lacklustre victory over Britain, came out on fire, scoring the first 10 points on the way to a massive 20-2 lead.
The Russians patiently clawed their way back, and when Fridzon and his team mates started finding the mark with their jump shots they went on a 12-4 run that helped get them to intermission trailing by just 40-32.
Russia limited Spain to only 12 points in the second quarter and 13 in the third quarter as they surged to a 56-53 lead.
The momentum swung back to Spain at the start of the fourth as the 2008 silver medallists used a 16-4 burst to lead 69-60.
A three-pointer by Victor Khryapa tied it at 73-73 with a minute to go and Timofey Mozgov's slam dunk put Russia ahead by two with 18 seconds left before Pau Gasol was sent to the line.
"Today, they killed us. Those three of them. They were extremely effective," Spain's Italian coach Sergio Scariolo said, singling out Fridzon, Anton Ponkrashov and Khryapa.
Ranked just 11th by the International Basketball Federation, Russia overcame Spain because of their team play, according to 31-year-old forward Andrei Kirilenko.
"I think our team has a face, our own face," said Kirilenko, who played 10 years with the NBA's Utah Jazz.
"We're playing hard. We don't have a lot of shooters, but I think we can do a lot of things together as a team. We stay in as a team and that's why we keep grinding those wins."