Anthony scored 31 points on the night he became the U.S. men's Olympic career scoring leader, combining with Irving for all the Americans' baskets in the fourth quarter of a 98-88 victory over Australia on Wednesday night.
Irving -- born in Australia -- added 19 points, including a 3-pointer with 1:35 left after Australia had closed within four.
A team that won its first two games by a combined 101 points could never get a comfortable lead -- and for a while couldn't get one at all. The Australians, with big bodies inside, quality point guards to counter the American pressure and a wealth of NBA championship experience, stood toe to toe with the team that had blown them out of the last two Olympics in the quarterfinals.
But Anthony, the most experienced U.S. player, the first male to play in four Olympics, steadied the Americans in the first competitive game most of this new team had never experienced.
Kevin Durant capped off the scoring with two free throws, making him the only other player than Irving or Anthony to score in the period.
The American, who had barely broken a sweat in Brazil, trailed early in the fourth quarter before Anthony hit a flurry of 3-pointers to put the Americans on top.
Patty Mills scored 30 points for Australia.
After blowouts of China and Venezuela to open the tournament, the Americans trailed 72-70 with about 9 minutes left. Anthony scored to tie it, hit a 3-pointer to give the Americans the lead for good, and then hit a couple more 3s that pushed it to 83-76.
The team staying on a luxury cruise ship could never relax until scoring the final five points in the last 27 seconds on free throws, with Irving hitting the first three.
The Americans were so carefree in their opener that reserves Jimmy Butler played rock, paper, scissors to determine who would shoot a free throw realized it was in a fight in this one.
An enraged coach Mike Krzyzewski screamed at an official after Andrew Bogut's hard foul on Irving just in front of the U.S. bench in the third quarter, his face looking as red as the shirts the coaching staff wore.
Bogut finished with 15 points for the Australians, who talked confidently of their chances in these Olympics. They have never won a medal but four of their players own NBA rings, and with smart passing and rugged rebounding, nearly became the first team to knock off the Americans in the Olympics since Krzyzewski took over in 2005.