World championship favourites the U.S. made it four wins out of four with an 88-51 victory over Iran on Wednesday while Angola booked a place in the last 16 with a stunning 92-88 overtime defeat of Germany.
Serbia also reached the knockout rounds with a match to spare after a 94-79 victory over Australia and holders Spain avoided an early exit, overcoming a poor start to demolish Lebanon 91-57.
The eagerly-awaited Group B clash between the U.S. and Iran was played in sporting fashion, with pockets of rival fans watching in a half-empty Abdi Ikpeci Arena.
Iran held their own in the first half and trailed by 14 points at the interval but the gulf in class was all too obvious after the break, with all 12 players on the U.S. roster getting on the scoresheet.
"We held our opponents for a long period and it was only in the last seven minutes we ran out of steam," Iran's Serbian coach Veselin Matic said.
"This is our first world championship and all this entertainment was good for us, it helped motivate my players to be at their best."
The teams applauded the fans and embraced each other after the match and Matic's U.S. counterpart Mike Krzyzewski praised Iran, whose centre Hamad Ehadadi finished as the game's top scorer with 19 points and five rebounds.
"The Iran team played really hard and had a really good game plan," he said.
Centre Tyson Chandler added: "It was a very good game and we had a lot of respect for each other."
Centre Kevin Love led the United States with 13 points, forward Kevin Durant added 12, guard Derrick Rose chipped in with 11 and Danny Granger scored 10 in a balanced team effort.
Germany's earlier win over Serbia turned out to be a flash in the pan as they lost to Group A rivals Angola, defeat sending them out of the 24-team event.
The African champions led throughout and although Germany somehow forced five additional minutes, they were undone by superb long-range shooting in overtime.
Olimpo Cipriano poured in 30 points and fellow forward Joaquim Gomez added 16 to go with 14 rebounds as Angola sank an impressive 18 three-pointers from 40 attempts.
Serbia welcomed captain Nenad Krstic back from suspension and playmaker Milos Teodosic and they were instrumental in the win over Australia that sealed a berth in the last 16.
Teodosic hit one three-pointer after another to keep Serbia ahead when the Australians closed in, finishing with a game-high 19 points while Krstic had 14 and 10 rebounds.
"We committed too many turnovers but dominated the offensive boards and Thursday's final Group A match against Argentina should be a feast," Serbia's trophy-laden coach Dusan Ivkovic said.
Still reeling from two defeats in their opening three Group D games, Spain trailed Lebanon 22-21 after the first quarter but eventually ran out comfortable winners on the back of 25 points and eight rebounds from centre Marc Gasol.
Lithuania stormed back from a 24-11 first-quarter deficit to beat France 69-55 in Group D.
In Group C, hosts Turkey rallied to maintain their perfect record with a 79-77 triumph over Puerto Rico and in Group B Slovenia beat Brazil 80-77.