Has a FIBA World Cup game ever ended 86-73?
It has. 86-73 has been a FIBA World Cup final 7 times in 2,041 games. The first was Yugoslavia beat Mexico on May 27, 1967; the latest was Nigeria beat China on September 8, 2019.
That makes 86-73 the 3rd most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 87-73 has happened 4 times and 86-74 has happened 4 times.