RIO DE JANEIRO: The US men’s team extended their Olympic unbeaten run to 21 games with a tense 94-91 win over Serbia on Friday, but their uneven play hinted that a third straight gold might not be a fait accompli. After opening the Rio Olympics with blowout wins over China and Venezuela, cracks are starting to show in the armour of a usually invincible US team that have been put to the test against Serbia and Australia in their last two games. While the US (4-0) lead Group A with one preliminary game remaining against France on Sunday, they have been plagued by turnovers in their last two contests and been unable to showcase the dominance that has long been their trademark. But despite some uneven play there was no panic in the US camp as players treated the near upsets as learning experiences ahead of the knockout phase of the 12-team tournament. “I’m not too concerned,” said Paul George, who had 12 points in the win while Kyrie Irving led the US with 15. “We’re a new group and playing against an experienced offense, we’re still trying to figure it out. “It’s good we’re having two games like these where we have to kind of pull it together. “Right now we we’re just going through an adjustment period.” Coming off Wednesday’s 98-88 win over Australia, the United States appeared to have learned their lesson as they got off to a fast start against Serbia. The Americans opened with a 14-2 run highlighted by a one-handed slam dunk from DeMarcus Cousins that triggered a round of high-fives from the American bench and signaled that a rout was underway. But sixth-ranked Serbia had other plans and denied the Americans a chance to put the game out of reach as they pulled to within nine points at halftime.