Jonas Maciulis led the eastern Europeans on Saturday with 19 points followed by Jonas Valanciunas with 17.
Jack Michael Martinez led a balanced Dominican attack with 13 points followed by Al Horford of the NBA's Atlanta Hawks with 12.
Also Saturday, Russia held off a late surge by a surprisingly strong Nigeria to also secure a ticket to London, winning 86-77.
The Dominicans play Nigeria on Sunday for the final Olympics spot from the FIBA qualifying tournament.