After a pair of early three-pointers by Pierre Hampton and Kendrick Brown, the visitors from Sweden took a 14-6 lead, looking to break away right from the get-go in the first quarter.
However, Rapla finished the quarter strong and trimmed the deficit to two points, as Andre Parnu swished in two free-throws to make it 22-24.
Dolphins shot ahead in the third quarter once again, breaking away from a 25-25 deadlock with an 8-0 run before pushing the advantage to double digits with another solid 7-1 stretch.
The visitors started the third period with a 45-33 lead, but it grew to a game-high 19 points in the third period after a made shot by William Walker.
Although Martin Dorbek had cut the deficit to single digits midway after scoring a lay-up midway through the final period, 56-65 was as close as Rapla would end up getting.
Edgaras Jeromanovs collected a game-high 17 points for the guests, William Walker scored 14 points, while Joakim Kjellbom chipped in with 11 points.
Rapla was led by Sven Kaldre, who had 12 points and five rebounds, as the young duo of Martin Dorbek and Rait-Riivo Laane added 11 points apiece.