The visitors started the game strong and took an early 12-6 lead after Maris Laksa went one-of-two from the free-throw stripe, but an 11-0 run put Jekabpils in front.
Tarvas got back in front on the second period and led for the majority of the time up to the halftime break, but the hosts held close and tied the game up at 40-40 after two quarters.
The game changed drastically in the second half, with Jekabpils finishing the third period with an 8-0 spurt, which put the home side up by double digits.
During the fourth quarter, the gap between the sides only grew and the Latvian hosts celebrated a convincing 28-point victory after a 31-point scoring outburst in the final period.
The American duo of Cameron Runders and Troy Barnies had 19 points apiece for the winners, with the latter also adding 11 rebounds. Janis Poznaks added 15 points and 15 rebounds.
Tarvas was led by Lithuanian point guard Giedrius Gustas, who was the only player in double digits for the visitors with 11 points, with Rait Keerles adding nine.